2023.04.07 Today's Challenge

https://leetcode.com/problems/number-of-enclaves/

Number of Enclaves - LeetCode

전형적인 dfs 문제

class Solution:
    def numEnclaves(self, grid: List[List[int]]) -> int:
        def dfs(i, j):
            grid[i][j] = 0
            for x, y in (i-1, j), (i+1, j), (i, j-1), (i, j+1):
                if 0 <= x < m and 0 <= y < n and grid[x][y]:
                    dfs(x, y)

        m, n = len(grid), len(grid[0])

        for i in range(m):
            for j in range(n):
                if grid[i][j] == 1 and (i == 0 or j == 0 or i == m -1 or j == n - 1):
                    dfs(i, j)
        
        return sum(sum(row) for row in grid)