Initial

2026-07-23 14:22:17 +08:00
commit f4d7f7899c
19 changed files with 407 additions and 0 deletions
@@ -0,0 +1,38 @@
+import itertools
+import sys
+from typing import Literal
+
+ROW_COUNT = 341_799
+MOD = 998_244_353
+
+PatternCharType = Literal[0, 1]
+
+
+def get_pattern_multiplier(pattern: tuple[PatternCharType, PatternCharType, PatternCharType]) -> int:
+    match pattern:
+        case (0, 0, 0) | (0, 0, 1) | (1, 0, 0) | (0, 1, 0) | (1, 0, 1): return 21 * 21
+        case (0, 1, 1) | (1, 1, 0): return 21 * 26
+        case (1, 1, 1): return 26 * 26
+        case _: raise ValueError(f"Unknown pattern: {pattern}")
+
+
+dp: dict[PatternCharType, list[tuple[int, int]]] = {0: [(-1, -1), (5, 0)], 1: [(-1, -1), (0, 21)]}
+
+for _ in range(ROW_COUNT - 1):
+    for c in 0, 1:
+        dp[c].append((dp[c][-1][1] * 5 % MOD, (dp[c][-1][0] + dp[c][-1][1]) * 21 % MOD))
+
+answer = 0
+
+for pattern1 in itertools.product([0, 1], repeat=3):
+    for pattern2 in itertools.product([0, 1], repeat=3):
+        # noinspection PyTypeChecker
+        answer += dp[pattern1[0]][ROW_COUNT][pattern2[0]] \
+                  * dp[pattern1[1]][ROW_COUNT][pattern2[1]] \
+                  * dp[pattern1[2]][ROW_COUNT][pattern2[2]] \
+                  * get_pattern_multiplier(pattern1) \
+                  * get_pattern_multiplier(pattern2) \
+                  % MOD
+
+print(dp[0][:100], dp[1][:100], file=sys.stderr, sep="\n")
+print(answer % MOD)