第二题 Python 这样写为啥 0% 啊，求大佬指教 import sys from typing import List readline = sys.stdin.readline def readint() -> int: return int(readline().strip()) def trans(s: str) -> int: return 1 if s == '.' else 0 def readints() -> List[int]: return list(map(trans, list(readline().strip()))) N = readint() vis = [[False] * (N + 1) for _ in range(N + 1)] matrix = [] number = 0 for i in range(N): s_list = readints() matrix.append(s_list) number += sum(s_list) ans = 0 def fb(x: int, y: int, num: int) -> None: if num == number: if x == N - 1: global ans ans += 1 return dx = [-1, 1, 0, 0] dy = [0, 0, -1, 1] for i in range(4): fx = x + dx[i] fy = y + dy[i] if 0 <= fx < N and 0 <= fy < N: if not vis[fx][fy] and matrix[fx][fy] == 1: vis[fx][fy] = True fb(fx, fy, num + 1) vis[fx][fy] = False vis[0][0] = True fb(0, 0, 1) print(ans)