- Problem

1020. Number of Enclaves

- 내 풀이 (BFS)

SEA = 0
LAND = 1
VISITED = -1

class Solution:
    def numEnclaves(self, grid: List[List[int]]) -> int:
        def bfs(y, x):
            q = deque([(y, x)])
            grid[y][x] = VISITED
            can_move = True
            moves = 1

            while q:
                y, x = q.popleft()
                if y in [0, M - 1] or x in [0, N - 1]:
                    can_move = False

                for dy, dx in ((-1, 0), (1, 0), (0, -1), (0, 1)):
                    ny = y + dy
                    nx = x + dx
                    if 0 <= ny < M and 0 <= nx < N and grid[ny][nx] == LAND:
                        q.append((ny, nx))
                        grid[ny][nx] = VISITED
                        moves += 1
            
            return moves if can_move else 0

        M, N = len(grid), len(grid[0])

        return sum(bfs(i, j) for i in range(M) for j in range(N) if grid[i][j] == LAND)

- 결과