Solution.py

class Solution:
    def containsCycle(self, grid: List[List[str]]) -> bool:
        m, n = len(grid), len(grid[0])
        vis = [[False] * n for _ in range(m)]
        dirs = (-1, 0, 1, 0, -1)
        for i, row in enumerate(grid):
            for j, x in enumerate(row):
                if vis[i][j]:
                    continue
                vis[i][j] = True
                q = [(i, j, -1, -1)]
                while q:
                    x, y, px, py = q.pop()
                    for dx, dy in pairwise(dirs):
                        nx, ny = x + dx, y + dy
                        if 0 <= nx < m and 0 <= ny < n:
                            if grid[nx][ny] != grid[i][j] or (nx == px and ny == py):
                                continue
                            if vis[nx][ny]:
                                return True
                            vis[nx][ny] = True
                            q.append((nx, ny, x, y))
        return False