some programs!!

cs101/sh_04_04_balloons.cpp

@@ -0,0 +1,26 @@
+/*
+ * 本来想打表的，打着打着发现了一些数学规律。具体怎么证明嘛……🤷‍
+ */
+
+#include <iostream>
+#include <cmath>
+
+constexpr size_t MAX_N = 10001;
+
+int get_ans(int n) {
+    const int k = ceil(-0.5 + 0.5 * sqrt(4 * n + 1));
+    const bool extra = k * k < n;
+    const int ans = k * (k - 1) + 1 + k * extra;
+    return ans;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    int n;
+    std::cin >> n;
+    std::cout << get_ans(n) << std::endl;
+
+    return 0;
+}