【leetcode每日一题】2022.02.12第1020题飞地的数量--回溯算法

class Solution(object):
    ans = 0
    def numEnclaves(self, grid):
        """
        :type grid: List[List[int]]
        :rtype: int
        也没复杂到用自动机
        """
        m=len(grid[0])
        n=len(grid)
        def DFS(i,j):
            if i>=0 and i<=n-1 and j<=m-1 and j>=0 and grid[i][j]==1:
                grid[i][j]=False
                self.ans-=1
                DFS(i-1,j)
                DFS(i+1,j,)
                DFS(i,j-1)
                DFS(i,j+1)
        for i in range(len(grid)):
            for j in range(len(grid[0])):
                if grid[i][j]==1:self.ans+=1
        for i in range(n):
            DFS(i,m-1)
            DFS(i,0)
        for j in range(m):
            DFS(0,j)
            DFS(n-1,j)
        return self.ans