链接
https://leetcode.cn/problems/number-of-islands/description/
思路
跟岛屿周长差不多...但我觉得这个比岛屿周长还简单。不知道为什么这个算中等题目，岛屿周长算简单题目
代码
class Solution: def numIslands(self, grid) -> int: if not grid or not grid[0]: return 0 height, width = len(grid), len(grid[0]) visited = [[False for i in range(width)] for i in range(height)] res = 0 direct_x = [0, 1, 0, -1] direct_y = [1, 0, -1, 0] def dfs(i, j, visited): if visited[i][j] or grid[i][j] == '0': return visited[i][j] = True for k in range(4): new_x, new_y = i + direct_x[k], j + direct_y[k] if 0 <= new_x < height and 0 <= new_y < width and not visited[new_x][new_y] and grid[new_x][new_y] == '1': dfs(new_x, new_y, visited) for i in range(height): for j in range(width): if not visited[i][j] and grid[i][j] == '1': res += 1 dfs(i, j, visited) return res