From 8bc1b22a1c270eda704f5290c750eef537d86e6b Mon Sep 17 00:00:00 2001
From: rogerwang2008 <rogerwang2008@163.com>
Date: Tue, 28 Jul 2026 00:33:27 +0800
Subject: [PATCH] 1

---
 .gitignore                                   |   7 +-
 .idea/codeStyles/codeStyleConfig.xml         |   5 +
 .idea/editor.xml                             |  93 +------------
 .idea/exercises.iml                          |   2 +
 .idea/inspectionProfiles/Project_Default.xml |   1 +
 .idea/workspace.xml                          | 130 ++++++++++++++-----
 pojcs101_M01002_memorable_number.cpp         |   1 -
 pojcs101_M01088_ski.cpp                      |  76 +++++++++++
 pojcs101_M01088_ski_WRONG.cpp                |  49 +++++++
 pojcs101_M01321_chest_grid.cpp               |  71 ++++++++++
 pojcs101_M01328_radar_greedy.cpp             |  59 +++++++++
 pojcs101_M01328_radar_greedy_WRONG.cpp       |  61 +++++++++
 pojcs101_M01852_ants_falling.cpp             |  40 ++++++
 pojcs101_M01922_ride_follower.cpp            |  58 +++++++++
 14 files changed, 529 insertions(+), 124 deletions(-)
 create mode 100644 .idea/codeStyles/codeStyleConfig.xml
 create mode 100644 .idea/exercises.iml
 create mode 100644 pojcs101_M01088_ski.cpp
 create mode 100644 pojcs101_M01088_ski_WRONG.cpp
 create mode 100644 pojcs101_M01321_chest_grid.cpp
 create mode 100644 pojcs101_M01328_radar_greedy.cpp
 create mode 100644 pojcs101_M01328_radar_greedy_WRONG.cpp
 create mode 100644 pojcs101_M01852_ants_falling.cpp
 create mode 100644 pojcs101_M01922_ride_follower.cpp

diff --git a/.gitignore b/.gitignore
index 424afbe..0c3d9d0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,7 @@
 .venv
-*.exe
+/*.exe
+
+# 忽略 linux 编译产物
+/*
+!/*.*
+!*/
\ No newline at end of file
diff --git a/.idea/codeStyles/codeStyleConfig.xml b/.idea/codeStyles/codeStyleConfig.xml
new file mode 100644
index 0000000..e402e4d
--- /dev/null
+++ b/.idea/codeStyles/codeStyleConfig.xml
@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="PREFERRED_PROJECT_CODE_STYLE" value="默认_mod" />
+  </state>
+</component>
\ No newline at end of file
diff --git a/.idea/editor.xml b/.idea/editor.xml
index 3f164bc..69ae789 100644
--- a/.idea/editor.xml
+++ b/.idea/editor.xml
@@ -206,7 +206,7 @@
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppStaticSpecifierOnAnonymousNamespaceMember/@EntryIndexedValue" value="SUGGESTION" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppStringLiteralToCharPointerConversion/@EntryIndexedValue" value="WARNING" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppTabsAreDisallowed/@EntryIndexedValue" value="DO_NOT_SHOW" type="string" />
-    <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppTemplateArgumentsCanBeDeduced/@EntryIndexedValue" value="HINT" type="string" />
+    <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppTemplateArgumentsCanBeDeduced/@EntryIndexedValue" value="DO_NOT_SHOW" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppTemplateParameterNeverUsed/@EntryIndexedValue" value="HINT" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppTemplateParameterShadowing/@EntryIndexedValue" value="WARNING" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppThrowExpressionCanBeReplacedWithRethrow/@EntryIndexedValue" value="WARNING" type="string" />
@@ -250,101 +250,18 @@
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=IfStdIsConstantEvaluatedCanBeReplaced/@EntryIndexedValue" value="SUGGESTION" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=StdIsConstantEvaluatedWillAlwaysEvaluateToConstant/@EntryIndexedValue" value="WARNING" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=StringLiteralTypo/@EntryIndexedValue" value="DO_NOT_SHOW" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppClangFormat/EnableClangFormatSupport/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_ARGUMENT/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_BINARY_EXPRESSIONS_CHAIN/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_CALLS_CHAIN/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_EXPRESSION/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_EXTENDS_LIST/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_FOR_STMT/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_PARAMETER/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_TYPE_ARGUMENT/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTILINE_TYPE_PARAMETER/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_MULTIPLE_DECLARATION/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALIGN_TERNARY/@EntryValue" value="ALIGN_ALL" type="string" />
+    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ALLOW_COMMENT_AFTER_LBRACE/@EntryValue" value="true" type="bool" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/ANONYMOUS_METHOD_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_CLASS_DEFINITION/@EntryValue" value="1" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_DECLARATIONS/@EntryValue" value="0" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_FUNCTION_DECLARATION/@EntryValue" value="1" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BLANK_LINES_AROUND_FUNCTION_DEFINITION/@EntryValue" value="1" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/BREAK_TEMPLATE_DECLARATION/@EntryValue" value="LINE_BREAK" type="string" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/CASE_BLOCK_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/CONTINUOUS_LINE_INDENT/@EntryValue" value="Double" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_ACCESS_SPECIFIERS_FROM_CLASS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_CASE_FROM_SWITCH/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_CLASS_MEMBERS_FROM_ACCESS_SPECIFIERS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_COMMENT/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_SIZE/@EntryValue" value="4" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INDENT_STYLE/@EntryValue" value="Space" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INITIALIZER_BRACES/@EntryValue" value="END_OF_LINE_NO_SPACE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INT_ALIGN_EQ/@EntryValue" value="false" type="bool" />
+    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/EMPTY_BLOCK_STYLE/@EntryValue" value="TOGETHER_SAME_LINE" type="string" />
+    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/EXPORT_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/INVOCABLE_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/KEEP_BLANK_LINES_IN_CODE/@EntryValue" value="2" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/KEEP_BLANK_LINES_IN_DECLARATIONS/@EntryValue" value="2" type="int" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/KEEP_USER_LINEBREAKS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/LINE_BREAK_AFTER_COLON_IN_MEMBER_INITIALIZER_LISTS/@EntryValue" value="ON_SINGLE_LINE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/MEMBER_INITIALIZER_LIST_STYLE/@EntryValue" value="DO_NOT_CHANGE" type="string" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/NAMESPACE_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/NAMESPACE_INDENTATION/@EntryValue" value="All" type="string" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/OTHER_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_CATCH_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_ELSE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_NAMESPACE_DEFINITIONS_ON_SAME_LINE/@EntryValue" value="false" type="bool" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/PLACE_WHILE_ON_NEW_LINE/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SIMPLE_BLOCK_STYLE/@EntryValue" value="DO_NOT_CHANGE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_CAST_EXPRESSION_PARENTHESES/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_COLON_IN_BITFIELD_DECLARATOR/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_COMMA_IN_TEMPLATE_ARGS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_COMMA_IN_TEMPLATE_PARAMS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_EXTENDS_COLON/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_FOR_COLON/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_FOR_SEMICOLON/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_DATA_MEMBER/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_DATA_MEMBERS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_METHOD/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_PTR_IN_NESTED_DECLARATOR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_REF_IN_DATA_MEMBER/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_REF_IN_DATA_MEMBERS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_REF_IN_METHOD/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_AFTER_UNARY_OPERATOR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_COLON_IN_BITFIELD_DECLARATOR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_EXTENDS_COLON/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_FOR_COLON/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_FOR_SEMICOLON/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_ABSTRACT_DECL/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_DATA_MEMBER/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_DATA_MEMBERS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_PTR_IN_METHOD/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_ABSTRACT_DECL/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_DATA_MEMBER/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_DATA_MEMBERS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_REF_IN_METHOD/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_TEMPLATE_ARGS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BEFORE_TEMPLATE_PARAMS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_BETWEEN_CLOSING_ANGLE_BRACKETS_IN_TEMPLATE_ARGS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_ARRAY_ACCESS_BRACKETS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_CAST_EXPRESSION_PARENTHESES/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_DECLARATION_PARENTHESES/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_BLOCKS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_INITIALIZER_BRACES/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_METHOD_PARENTHESES/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_EMPTY_TEMPLATE_PARAMS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_INITIALIZER_BRACES/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_TEMPLATE_ARGS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPACE_WITHIN_TEMPLATE_PARAMS/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/SPECIAL_ELSE_IF_TREATMENT/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/TAB_WIDTH/@EntryValue" value="4" type="int" />
+    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/REQUIRES_EXPRESSION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
     <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/TYPE_DECLARATION_BRACES/@EntryValue" value="END_OF_LINE" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_AFTER_BINARY_OPSIGN/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_AFTER_DECLARATION_LPAR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_AFTER_INVOCATION_LPAR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_ARGUMENTS_STYLE/@EntryValue" value="WRAP_IF_LONG" type="string" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_DECLARATION_LPAR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_DECLARATION_RPAR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_INVOCATION_LPAR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_INVOCATION_RPAR/@EntryValue" value="false" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_BEFORE_TERNARY_OPSIGNS/@EntryValue" value="true" type="bool" />
-    <option name="/Default/CodeStyle/CodeFormatting/CppFormatting/WRAP_PARAMETERS_STYLE/@EntryValue" value="WRAP_IF_LONG" type="string" />
-    <option name="/Default/CodeStyle/EditorConfig/EnableClangFormatSupport/@EntryValue" value="false" type="bool" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/exercises.iml b/.idea/exercises.iml
new file mode 100644
index 0000000..4c94235
--- /dev/null
+++ b/.idea/exercises.iml
@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module classpath="CIDR" type="CPP_MODULE" version="4" />
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
index 2ca729b..b4af121 100644
--- a/.idea/inspectionProfiles/Project_Default.xml
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -1,6 +1,7 @@
 <component name="InspectionProjectProfileManager">
   <profile version="1.0">
     <option name="myName" value="Project Default" />
+    <inspection_tool class="CppTemplateArgumentsCanBeDeduced" enabled="false" level="HINT" enabled_by_default="false" />
     <inspection_tool class="CppUseInternalLinkage" enabled="false" level="WEAK WARNING" enabled_by_default="false" />
   </profile>
 </component>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index c9bc359..f81f1bc 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -4,19 +4,46 @@
     <option name="autoReloadType" value="SELECTIVE" />
   </component>
   <component name="BackendCodeEditorMiscSettings">
+    <option name="/Default/Environment/Hierarchy/GeneratedFilesCacheKey/Timestamp/@EntryValue" value="8" type="long" />
     <option name="/Default/Housekeeping/FeatureSuggestion/FeatureSuggestionManager/DisabledSuggesters/=SwitchToGoToActionSuggester/@EntryIndexedValue" value="true" type="bool" />
     <option name="/Default/Housekeeping/LiveTemplatesHousekeeping/HotspotSessionHintIsShown/@EntryValue" value="true" type="bool" />
     <option name="/Default/Housekeeping/OptionsDialog/SelectedPageId/@EntryValue" value="CppFormatterOtherPage" type="string" />
   </component>
+  <component name="CMakePresetLoader">{
+  &quot;useNewFormat&quot;: true
+}</component>
+  <component name="CMakeProjectFlavorService">
+    <option name="flavorId" value="CMakePlainProjectFlavor" />
+  </component>
+  <component name="CMakeReloadState">
+    <option name="reloaded" value="true" />
+  </component>
+  <component name="CMakeRunConfigurationManager">
+    <generated>
+      <config projectName="Project" targetName="exercises" />
+    </generated>
+  </component>
+  <component name="CMakeSettings">
+    <configurations>
+      <configuration PROFILE_NAME="Debug" ENABLED="true" CONFIG_NAME="Debug" />
+    </configurations>
+  </component>
   <component name="ChangeListManager">
-    <list default="true" id="4491295e-723c-4e0b-b7b4-9be1cbde5db8" name="更改" comment="">
-      <change afterPath="$PROJECT_DIR$/lc_127.py" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/pojcs101_M01017_6_boxes.cpp" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/pojcs101_M02692_12_coins.cpp" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/pojcs101_M02692_12_coins_WRONG.cpp" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/.idea/exercises.iml" beforeDir="false" />
+    <list default="true" id="4491295e-723c-4e0b-b7b4-9be1cbde5db8" name="更改" comment="fix gitignore">
+      <change afterPath="$PROJECT_DIR$/.idea/codeStyles/codeStyleConfig.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/.idea/exercises.iml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01088_ski.cpp" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01088_ski_WRONG.cpp" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01321_chest_grid.cpp" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01328_radar_greedy.cpp" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01328_radar_greedy_WRONG.cpp" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01852_ants_falling.cpp" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/pojcs101_M01922_ride_follower.cpp" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.gitignore" beforeDir="false" afterPath="$PROJECT_DIR$/.gitignore" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/editor.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/editor.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/inspectionProfiles/Project_Default.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/inspectionProfiles/Project_Default.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/pojcs101_M01002.cpp" beforeDir="false" afterPath="$PROJECT_DIR$/pojcs101_M01002_memorable_number.cpp" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/pojcs101_M01002_memorable_number.cpp" beforeDir="false" afterPath="$PROJECT_DIR$/pojcs101_M01002_memorable_number.cpp" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -25,10 +52,12 @@
   </component>
   <component name="ClangdSettings">
     <option name="formatViaClangd" value="false" />
+    <option name="clangWarnings" value="-Wno-unused-variable,-Wno-infinite-recursion,-Wno-array-bounds,-Wno-return-stack-address,-Werror=implicit-function-declaration,-Wshadow,-Wno-shadow-field-in-constructor-modified,-Wno-shadow-ivar,-Wuninitialized,-Wunused-label,-Wunused-lambda-capture,-std=c++17" />
   </component>
   <component name="CurrentDebugProfile">
-    <option name="debugProfileId" value="e77b0a9f-756a-4aba-8623-5e4caeda05ed" />
+    <option name="debugProfileId" value="2c1c9069-eeff-46e4-9092-db62e2b1ded5" />
   </component>
+  <component name="ExecutionTargetManager" SELECTED_TARGET="CMakeBuildProfile:Debug" />
   <component name="FileTemplateManagerImpl">
     <option name="RECENT_TEMPLATES">
       <list>
@@ -38,11 +67,22 @@
     </option>
   </component>
   <component name="Git.Settings">
+    <option name="RECENT_BRANCH_BY_REPOSITORY">
+      <map>
+        <entry key="$PROJECT_DIR$" value="main" />
+      </map>
+    </option>
     <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
   </component>
   <component name="MacroExpansionManager">
     <option name="directoryName" value="7Sv2hfws" />
   </component>
+  <component name="ProjectApplicationVersion">
+    <option name="ide" value="CLion" />
+    <option name="majorVersion" value="2026" />
+    <option name="minorVersion" value="2.0.1" />
+    <option name="productBranch" value="Classic" />
+  </component>
   <component name="ProjectColorInfo">{
   &quot;customColor&quot;: &quot;&quot;,
   &quot;associatedIndex&quot;: 6
@@ -54,6 +94,7 @@
   </component>
   <component name="PropertiesComponent"><![CDATA[{
   "keyToString": {
+    "ASKED_SHARE_PROJECT_CONFIGURATION_FILES": "true",
     "C/C++ 文件.D_pojcs101_M02692.cpp.executor": "Run",
     "C/C++ 文件.luogu_UVA755.cpp.executor": "Run",
     "C/C++ 文件.luogu_ez_B3628.cpp.executor": "Run",
@@ -61,20 +102,30 @@
     "C/C++ 文件.ojcs101_E01218.cpp.executor": "Run",
     "C/C++ 文件.ojcs101_E02883.cpp.executor": "Run",
     "C/C++ 文件.pojcs101_M01017_6_boxes.cpp.executor": "Run",
+    "C/C++ 文件.pojcs101_M01088_ski.cpp.executor": "Run",
+    "C/C++ 文件.pojcs101_M01321_chest_grid.cpp.executor": "Debug",
+    "C/C++ 文件.pojcs101_M01328_radar_greedy.cpp.executor": "Debug",
+    "C/C++ 文件.pojcs101_M01852_ants_falling.cpp.executor": "Run",
+    "C/C++ 文件.pojcs101_M01922_ride_follower.cpp.executor": "Run",
     "C/C++ 文件.pojcs101_M02692.cpp.executor": "Run",
+    "C/C++ 文件.pojcs101_M02692_12_coins.cpp.executor": "Run",
+    "CMake 应用程序.exercises.executor": "Run",
     "CidrDebugProfileConversion": "true",
     "ModuleVcsDetector.initialDetectionPerformed": "true",
     "Python.lc_127.executor": "Run",
     "RunOnceActivity.RadMigrateCodeStyle": "true",
     "RunOnceActivity.ShowReadmeOnStart": "true",
     "RunOnceActivity.cidr.known.project.marker": "true",
+    "RunOnceActivity.git.unshallow": "true",
     "RunOnceActivity.readMode.enableVisualFormatting": "true",
     "RunOnceActivity.typescript.service.memoryLimit.init": "true",
+    "RunOnceActivity.west.config.association.type.startup.service": "true",
+    "SHARE_PROJECT_CONFIGURATION_FILES": "true",
     "cf.first.check.clang-format": "false",
     "cidr.known.project.marker": "true",
     "codeWithMe.voiceChat.enabledByDefault": "false",
     "git-widget-placeholder": "main",
-    "last_opened_file_path": "E:/Projects/exercises",
+    "last_opened_file_path": "/Users/roger/coding/exercises",
     "node.js.detected.package.jshint": "true",
     "node.js.selected.package.jshint": "",
     "nodejs_package_manager_path": "npm",
@@ -82,43 +133,37 @@
     "settings.editor.selected.configurable": "preferences.sourceCode.C++"
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 }]]></component>
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-      <option name="sourceFile" value="D_pojcs101_M02692.cpp" />
+  <component name="RecentsManager">
+    <key name="CopyFile.RECENT_KEYS">
+      <recent name="$PROJECT_DIR$" />
+    </key>
+  </component>
+  <component name="RunManager" selected="C/C++ 文件.pojcs101_M01922_ride_follower.cpp">
+    <configuration name="pojcs101_M01328_radar_greedy.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="pojcs101_M01328_radar_greedy.cpp" CONFIG_NAME="pojcs101_M01328_radar_greedy.cpp">
+      <option name="sourceFile" value="pojcs101_M01328_radar_greedy.cpp" />
       <method v="2">
         <option name="com.jetbrains.cidr.cpp.runfile.CppFileBuildBeforeRunTaskProvider$BasicBuildBeforeRunTask" enabled="true" />
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     </configuration>
-    <configuration name="luogu_UVA755.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="luogu_UVA755.cpp" CONFIG_NAME="luogu_UVA755.cpp">
-      <option name="sourceFile" value="luogu_UVA755.cpp" />
+    <configuration name="pojcs101_M01852_ants_falling.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="pojcs101_M01852_ants_falling.cpp" CONFIG_NAME="pojcs101_M01852_ants_falling.cpp">
+      <option name="sourceFile" value="pojcs101_M01852_ants_falling.cpp" />
       <method v="2">
         <option name="com.jetbrains.cidr.cpp.runfile.CppFileBuildBeforeRunTaskProvider$BasicBuildBeforeRunTask" enabled="true" />
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-    <configuration name="ojcs101_E01218.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="ojcs101_E01218.cpp" CONFIG_NAME="ojcs101_E01218.cpp">
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-    <configuration name="ojcs101_E02883.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="ojcs101_E02883.cpp" CONFIG_NAME="ojcs101_E02883.cpp">
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-        <option name="com.jetbrains.cidr.cpp.runfile.CppFileBuildBeforeRunTaskProvider$BasicBuildBeforeRunTask" enabled="true" />
-      </method>
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-    <configuration name="pojcs101_M01017_6_boxes.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="pojcs101_M01017_6_boxes.cpp" CONFIG_NAME="pojcs101_M01017_6_boxes.cpp">
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-    <configuration name="pojcs101_M02692.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="pojcs101_M02692.cpp" CONFIG_NAME="pojcs101_M02692.cpp">
-      <option name="sourceFile" value="pojcs101_M02692.cpp" />
+    <configuration name="pojcs101_M01922_ride_follower.cpp" type="CppFileRunConfiguration" factoryName="CppFileRunConfiguration" temporary="true" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="exercises" TARGET_NAME="pojcs101_M01922_ride_follower.cpp" CONFIG_NAME="pojcs101_M01922_ride_follower.cpp">
+      <option name="sourceFile" value="pojcs101_M01922_ride_follower.cpp" />
       <method v="2">
         <option name="com.jetbrains.cidr.cpp.runfile.CppFileBuildBeforeRunTaskProvider$BasicBuildBeforeRunTask" enabled="true" />
       </method>
     </configuration>
+    <recent_temporary>
+      <list>
+        <item itemvalue="C/C++ 文件.pojcs101_M01922_ride_follower.cpp" />
+        <item itemvalue="C/C++ 文件.pojcs101_M01852_ants_falling.cpp" />
+        <item itemvalue="C/C++ 文件.pojcs101_M01328_radar_greedy.cpp" />
+      </list>
+    </recent_temporary>
   </component>
   <component name="SharedIndexes">
     <attachedChunks>
@@ -142,10 +187,27 @@
   <component name="TypeScriptGeneratedFilesManager">
     <option name="version" value="3" />
   </component>
+  <component name="VCPKGProject">
+    <isAutomaticCheckingOnLaunch value="false" />
+    <isAutomaticFoundErrors value="true" />
+    <isAutomaticReloadCMake value="true" />
+    <isAutomaticBootstrapAfterUpdate value="false" />
+  </component>
   <component name="VcsManagerConfiguration">
     <MESSAGE value="1" />
     <option name="LAST_COMMIT_MESSAGE" value="1" />
   </component>
+  <component name="XDebuggerManager">
+    <breakpoint-manager>
+      <breakpoints>
+        <line-breakpoint enabled="true" type="com.jetbrains.cidr.execution.debugger.OCBreakpointType">
+          <url>file://$PROJECT_DIR$/pojcs101_M01321_chest_grid.cpp</url>
+          <line>44</line>
+          <option name="timeStamp" value="2" />
+        </line-breakpoint>
+      </breakpoints>
+    </breakpoint-manager>
+  </component>
   <component name="XSLT-Support.FileAssociations.UIState">
     <expand />
     <select />
diff --git a/pojcs101_M01002_memorable_number.cpp b/pojcs101_M01002_memorable_number.cpp
index c3c26a4..9976c06 100644
--- a/pojcs101_M01002_memorable_number.cpp
+++ b/pojcs101_M01002_memorable_number.cpp
@@ -40,7 +40,6 @@ void runDataset() {
     if (noDuplicate) {
         std::cout << "No duplicates." << std::endl;
     }
-    // std::cout << std::endl;
 }
 
 int main() {
diff --git a/pojcs101_M01088_ski.cpp b/pojcs101_M01088_ski.cpp
new file mode 100644
index 0000000..8ca0542
--- /dev/null
+++ b/pojcs101_M01088_ski.cpp
@@ -0,0 +1,76 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+constexpr int DX[] = {0, 1, 0, -1};
+constexpr int DY[] = {1, 0, -1, 0};
+
+int path_length = 0;
+
+void log_grid(const vector<vector<int>>& grid, string name) {
+    for (const auto& row : grid) {
+        clog << name << ": ";
+        for (const auto& cell : row) {
+            clog << cell << " ";
+        }
+        clog << endl;
+    }
+}
+
+int dfs(const vector<vector<int>>& grid, const int x, const int y,
+        vector<vector<int>>& calculated_depths, const int _depth = 1) {
+    const unsigned int r = grid.size(), c = grid[0].size();
+
+    const int current_num = grid[x][y];
+    if (calculated_depths[x][y] > 0) { return calculated_depths[x][y] + _depth - 1; }
+
+    if (_depth + current_num <= path_length) {
+        // clog << "CUT " << x << "," << y << ":" << current_num << ", " << _depth << endl;
+        return -1;
+    } // 剪枝
+    // if (current_num == 1) { return _depth; }
+    // clog << x << "," << y << ":" << current_num << ", " << _depth << endl;
+
+    int best_depth = _depth;
+
+    for (int i = 0; i < 4; i++) {
+        const int nx = x + DX[i], ny = y + DY[i];
+        if (nx >= 0 && nx < r && ny >= 0 && ny < c && grid[nx][ny] < current_num) {
+            int next_depth = dfs(grid, nx, ny, calculated_depths, _depth + 1);
+            best_depth = max(best_depth, next_depth);
+        }
+    }
+    path_length = max(path_length, best_depth);
+    calculated_depths[x][y] = best_depth - _depth + 1;
+    return best_depth;
+}
+
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int r, c;
+    cin >> r >> c;
+
+    vector<vector<int>> grid(r, vector<int>(c));
+    vector<vector<int>> calculated_depths(r, vector<int>(c, 0));
+
+    for (int i = 0; i < r; i++) {
+        for (int j = 0; j < c; j++) {
+            cin >> grid[i][j];
+        }
+    }
+    for (int i = 0; i < r; i++) {
+        for (int j = 0; j < c; j++) {
+            dfs(grid, i, j, calculated_depths);
+            // clog << "---" << endl;
+            // log_grid(calculated_depths, "calculated_depths");
+            // clog << "---" << endl;
+        }
+    }
+    cout << path_length << endl;
+
+    return 0;
+}
diff --git a/pojcs101_M01088_ski_WRONG.cpp b/pojcs101_M01088_ski_WRONG.cpp
new file mode 100644
index 0000000..9d94529
--- /dev/null
+++ b/pojcs101_M01088_ski_WRONG.cpp
@@ -0,0 +1,49 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+constexpr int DX[] = {0, 1, 0, -1};
+constexpr int DY[] = {1, 0, -1, 0};
+
+int longest_path(const vector<vector<int> > &grid, int x = -1, int y = -1, int depth = 0) {
+    const unsigned int r = grid.size(), c = grid[0].size();
+    if (x == -1 && y == -1) {
+        for (int i = 0; i < r; i++) {
+            for (int j = 0; j < c; j++) {
+                if (grid[i][j] == r * c) {
+                    x = i, y = j, depth = 1;
+                    break;
+                }
+            }
+        }
+    }
+
+    for (int i = 0; i < 4; i++) {
+        int nx = x + DX[i], ny = y + DY[i];
+        if (nx >= 0 && nx < grid.size() && ny >= 0 && ny < grid[0].size()
+            && grid[nx][ny] == grid[x][y] - 1) {
+            return longest_path(grid, nx, ny, depth + 1);
+        }
+    }
+    return depth;
+}
+
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int r, c;
+    cin >> r >> c;
+
+    vector<vector<int> > grid(r, vector<int>(c));
+    for (int i = 0; i < r; i++) {
+        for (int j = 0; j < c; j++) {
+            cin >> grid[i][j];
+        }
+    }
+    cout << longest_path(grid) << endl;
+
+    return 0;
+}
diff --git a/pojcs101_M01321_chest_grid.cpp b/pojcs101_M01321_chest_grid.cpp
new file mode 100644
index 0000000..c010401
--- /dev/null
+++ b/pojcs101_M01321_chest_grid.cpp
@@ -0,0 +1,71 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+void log_array(const vector<bool>& arr, const string& name) {
+    clog << name << ": ";
+    for (const auto& cell : arr) {
+        clog << cell << " ";
+    }
+    clog << endl;
+}
+
+vector<vector<bool>> get_grid(const int size) {
+    vector<vector<bool>> grid;
+    for (int _ = 0; _ < size; _++) {
+        string pattern;
+        vector<bool> row;
+        cin >> pattern;
+        for (const char c : pattern) { row.push_back(c != '.'); }
+        grid.push_back(row);
+    }
+    return grid;
+}
+
+long long dfs(const vector<vector<bool>>& grid,
+              const int remaining_chests,
+              const int curr_empty_row,
+              vector<bool>& col_occupation) {
+    const unsigned int size = grid[0].size();
+    if (remaining_chests == 0) { return 1; }
+    if (curr_empty_row >= size) { return 0; }
+    // clog << "curr_empty_row: " << curr_empty_row << endl;
+    // log_array(col_occupation, "col_occupation");
+    long long ans = 0;
+    for (int col = 0; col < size; col++) { // 这行放
+        if (!grid[curr_empty_row][col]) { continue; }
+        if (col_occupation[col]) { continue; }
+        // vector<bool> new_col_occupation(col_occupation);
+        col_occupation[col] = true;
+        ans += dfs(grid, remaining_chests - 1, curr_empty_row + 1, col_occupation);
+        col_occupation[col] = false;
+    }
+    ans += dfs(grid, remaining_chests, curr_empty_row + 1, col_occupation); // 不在这行放
+    return ans;
+}
+
+long long dfs(const vector<vector<bool>>& grid,
+              const int remaining_chests,
+              const int curr_empty_row = 0) {
+    vector<bool> col_occupation(grid[0].size(), false);
+    return dfs(grid, remaining_chests, curr_empty_row, col_occupation);
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int size, chest_count;
+    while (cin >> size >> chest_count) {
+        if (size < 0) { break; }
+        vector<vector<bool>> grid = get_grid(size);
+        cout << dfs(grid, chest_count) << endl;
+    }
+    // cin >> size;
+    // chest_count = size;
+    // const vector<vector<bool>> grid = get_grid(size);
+    // cout << dfs(grid, chest_count) << endl;
+
+    return 0;
+}
diff --git a/pojcs101_M01328_radar_greedy.cpp b/pojcs101_M01328_radar_greedy.cpp
new file mode 100644
index 0000000..4c7595a
--- /dev/null
+++ b/pojcs101_M01328_radar_greedy.cpp
@@ -0,0 +1,59 @@
+#include <iostream>
+#include <vector>
+#include <cmath>
+#include <algorithm>
+
+using namespace std;
+
+double other_leg(const double leg, const double diag) {
+    return sqrt(diag * diag - leg * leg);
+}
+
+double diag(const double leg1, const double leg2) {
+    return sqrt(leg1 * leg1 + leg2 * leg2);
+}
+
+vector<pair<double, double>> target_ranges(vector<pair<int, int>> islands, const int distance) {
+    vector<pair<double, double>> ranges;
+    for (auto& [island_x, island_y] : islands) {
+        if (island_y > distance) { throw std::runtime_error("Island is too far away from the radar."); }
+        const double offset = other_leg(island_y, distance);
+        ranges.emplace_back(island_x - offset, island_x + offset);
+    }
+    sort(ranges.begin(), ranges.end(),
+         [](const auto& a, const auto& b) { return a.second < b.second; });
+    return ranges;
+}
+
+int required_radars(const vector<pair<double, double>>& ranges) {
+    if (ranges.empty()) { return 0; }
+    int answer = 1;
+    double current_max_x = ranges[0].second;
+    for (const auto& [left,right] : ranges) {
+        if (left > current_max_x) { answer++, current_max_x = right; } // 放不下，加雷达
+        else if (right < current_max_x) { current_max_x = right; } // 放下，需要左移雷达
+        clog << "current_max_x: " << current_max_x << " answer: " << answer << endl;
+    }
+    return answer;
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n, distance, case_id = 0;
+    while (cin >> n >> distance) {
+        if (n == 0 && distance == 0) { break; }
+        vector<pair<int, int>> islands(n);
+        for (int i = 0; i < n; i++) {
+            cin >> islands[i].first >> islands[i].second;
+        }
+        // cout << "Case " << ++case_id << ": ";
+        try {
+            cout << required_radars(target_ranges(islands, distance)) << endl;
+        } catch (std::runtime_error&) {
+            cout << -1 << endl;
+        }
+    }
+}
+
diff --git a/pojcs101_M01328_radar_greedy_WRONG.cpp b/pojcs101_M01328_radar_greedy_WRONG.cpp
new file mode 100644
index 0000000..c090542
--- /dev/null
+++ b/pojcs101_M01328_radar_greedy_WRONG.cpp
@@ -0,0 +1,61 @@
+#include <iostream>
+#include <vector>
+#include <cmath>
+#include <algorithm>
+
+
+using namespace std;
+
+double other_leg(const double leg, const double diag) {
+    return sqrt(diag * diag - leg * leg);
+}
+
+double diag(const double leg1, const double leg2) {
+    return sqrt(leg1 * leg1 + leg2 * leg2);
+}
+
+int required_radars(vector<pair<int, int>> islands, int distance) {
+    for (auto& [island_x, island_y] : islands) {
+        if (island_y > distance) { return -1; }
+    }
+    sort(islands.begin(), islands.end());
+    int answer = 0;
+    while (!islands.empty()) {
+        answer++;
+        const auto current_island = islands.back();
+        islands.pop_back();
+        double min_x = current_island.first
+            - other_leg(current_island.second, distance)
+            - current_island.second;
+        vector<pair<int, int>> uncovered_islands;
+        while (!islands.empty() && islands.back().first >= min_x) {
+            // 右移雷达
+            const double offset = other_leg(islands.back().second, distance);
+            if (islands.back().first - offset >= min_x) {
+                min_x = islands.back().first - offset;
+            } else {
+                uncovered_islands.push_back(islands.back());
+            }
+            islands.pop_back();
+        }
+        for (int i = uncovered_islands.size() - 1; i >= 0; i--) { // NOLINT(*-narrowing-conversions)
+            islands.push_back(uncovered_islands[i]);
+        }
+    }
+    return answer;
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n, distance, case_id = 0;
+    while (cin >> n >> distance) {
+        if (n == 0 && distance == 0) { break; }
+        vector<pair<int, int>> islands(n);
+        for (int i = 0; i < n; i++) {
+            cin >> islands[i].first >> islands[i].second;
+        }
+        cout << "Case " << ++case_id << ": " << required_radars(islands, distance) << endl;
+    }
+}
diff --git a/pojcs101_M01852_ants_falling.cpp b/pojcs101_M01852_ants_falling.cpp
new file mode 100644
index 0000000..328dfea
--- /dev/null
+++ b/pojcs101_M01852_ants_falling.cpp
@@ -0,0 +1,40 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+int shortest_fall_time(const int length, vector<int> ant_pos) {
+    sort(ant_pos.begin(), ant_pos.end(),
+         [length](const int pos1, const int pos2) {
+             return abs(pos1 - length / 2) < abs(pos2 - length / 2); // 到中点距离最短者
+         });
+    return min(ant_pos[0], length - ant_pos[0]);
+}
+
+int longest_fall_time(const int length, vector<int> ant_pos) {
+    sort(ant_pos.begin(), ant_pos.end(),
+         [length](const int pos1, const int pos2) {
+             return abs(pos1 - length / 2) > abs(pos2 - length / 2); // 到中点距离最长者
+         });
+    return max(ant_pos[0], length - ant_pos[0]);
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int group_count;
+    cin >> group_count;
+    for (int _ = 0; _ < group_count; _++) {
+        int length, ant_count;
+        cin >> length >> ant_count;
+        vector<int> ant_pos(ant_count);
+        for (int i = 0; i < ant_count; i++) {
+            cin >> ant_pos[i];
+        }
+        cout << shortest_fall_time(length, ant_pos) << " " << longest_fall_time(length, ant_pos) << endl;
+    }
+
+    return 0;
+}
diff --git a/pojcs101_M01922_ride_follower.cpp b/pojcs101_M01922_ride_follower.cpp
new file mode 100644
index 0000000..5dfbdd9
--- /dev/null
+++ b/pojcs101_M01922_ride_follower.cpp
@@ -0,0 +1,58 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+#include <cmath>
+
+using namespace std;
+
+typedef pair<int, int> Rider;
+
+constexpr int FULL_DISTANCE = 4500 * 3.6;
+
+int ride_time(const Rider& rider, const int distance = FULL_DISTANCE) {
+    return static_cast<int>(ceil(static_cast<double>(distance) / rider.first)) + rider.second;
+}
+
+int start_pos(const Rider& rider) {
+    if (rider.second >= 0) { return 0; }
+    return rider.first * -rider.second;
+}
+
+int arrival_time(const vector<Rider>& riders, const int distance = FULL_DISTANCE) {
+    vector<Rider> early_riders, late_riders;
+    for (const auto& rider : riders) {
+        if (rider.second >= 0) {
+            late_riders.push_back(rider);
+        } else {
+            // early_riders.push_back(rider);
+        }
+    }
+    double min_time = ride_time(*min_element(
+        late_riders.begin(), late_riders.end(),
+        [distance](const Rider& a, const Rider& b) {
+            return ride_time(a, distance) < ride_time(b, distance);
+        }));
+    clog << "min_time: " << min_time << endl;
+    // for (const auto& rider : early_riders) {
+    //     if (-rider.second > min_time) { continue; }
+    //     min_time = min(min_time, ride_time(rider, distance));
+    // }
+    return static_cast<int>(ceil(min_time));
+}
+
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+    int rider_count;
+    while (cin >> rider_count && rider_count) {
+        vector<Rider> riders(rider_count);
+        for (int i = 0; i < rider_count; i++) {
+            cin >> riders[i].first >> riders[i].second;
+            // riders[i].first /= 3.6;
+        }
+        cout << arrival_time(riders) << endl;
+    }
+
+    return 0;
+}