题解 | #岛屿数量#

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 判断岛屿数量
# @param grid char字符型二维数组 
# @return int整型
#
class Solution:
    def solve(self , grid: List[List[str]]) -> int:
        # write code here
        if not grid or not grid[0]:
            return 0
        m,n = len(grid),len(grid[0])
        res = 0
        for i in range(m):
            for j in range(n):
                if grid[i][j] == '1':
                    res += 1
                    self.dfs(grid,i,j)
        return res
    
    def dfs(self,grid,i,j):
        if i<0 or i>=len(grid) or j<0 or j>=len(grid[0]) or grid[i][j]=='0':
            return
        grid[i][j] = '0'
        self.dfs(grid,i-1,j)
        self.dfs(grid,i+1,j)
        self.dfs(grid,i,j-1)
        self.dfs(grid,i,j+1)