leetcode200. 岛屿数量

leetcode200. 岛屿数量

题目

思路

遍历每一个网格，若网格为1，岛屿数量+1，利用一个深度优先搜索函数将岛屿置零，注意判断数组边界

代码

class Solution:
    def numIslands(self, grid: List[List[str]]) -> int:
        self.grid = grid
        self.result = 0
        self.height = len(grid)
        self.width = len(grid[0])
        self.directions = [[-1,0],[1,0],[0,-1],[0,1]]
        for i in range(self.height):
            for j in range(self.width):
                if self.grid[i][j]=='1':
                    self.result += 1
                    self.clean(i,j)
        return self.result

    def clean(self,i,j):
        if self.grid[i][j]=='1':  # 终止前置条件
            self.grid[i][j]='0'
        else:                     # 终止前置条件
            return 0
        for direction in self.directions:
            temp_h = i+direction[0]
            temp_w = j+direction[1]
            if temp_h>=0 and temp_h<self.height and temp_w>=0 and temp_w<self.width:
                self.clean(temp_h,temp_w)