leetcode刷题日记-岛屿数量
题目描述
题目描述
这道题目一开始并没有思路去思考，看了题解之后才慢慢的理解这个的意思。相当于dfs的变体，类似于判断拓扑路径。
##代码实现
class Solution:def numIslands(self, grid: List[List[str]]) -> int:row,col=len(grid),len(grid[0])count=0visited=[[False]*col for _ in range(row)]directions=[[0,-1],[1,0],[0,1],[-1,0]]def outrange(x,y):if x<0 or x>=row or y<0 or y>=col:return Falseelse:return Truedef dfs(x,y):visited[x][y]=Truefor dx,dy in directions:newx,newy=x+dx,y+dyif outrange(newx,newy) and not visited[newx][newy] and grid[newx][newy]=='1':dfs(newx,newy)for i in range(row):for j in range(col):if grid[i][j] =='1' and not visited[i][j]:dfs(i,j)count+=1return count