学习资料：https://www.programmercarl.com/kamacoder/0099.岛屿的数量深搜.html#思路
深度优先搜索和广度优先搜索
今天用的邻接矩阵
学习记录：
卡码网99.岛屿数量 （深搜or广搜；用一个自己设计的二维矩阵来控制节点的移动方向：上下左右）
点击查看代码
from collections import deque
direction = [[1,0], [0,1], [-1,0], [0, -1]] # 上，右，下，左def bfs(visited, grid, x, y):"""广搜"""que = deque([])que.append([x, y])while que:cur_x, cur_y = que.popleft()for i, j in direction:next_x = cur_x + inext_y = cur_y + jif next_x<0 or next_x>=len(grid) or next_y<0 or next_y>=len(grid[0]):continueif not visited[next_x][next_y] and grid[next_x][next_y] == 1:visited[next_x][next_y] = Trueque.append([next_x, next_y])def dfs(visited, grid, x, y):"""深搜"""for i, j in direction:next_x = x+inext_y = y + j# 下标越界，跳过 (这一小片区域的边界)if next_x<0 or next_x>=len(grid) or next_y<0 or next_y>=len(grid[0]):continue# 遇到为访问的陆地，标记并使用深搜if not visited[next_x][next_y] and grid[next_x][next_y]==1:visited[next_x][next_y] = Truedfs(visited, grid, next_x, next_y)if __name__ == "__main__":n, m = map(int, input().split())# 构造邻接矩阵grid = []for i in range(n):grid.append(list(map(int, input().split())))# 构造访问表，若以访问则为Truevisited = [[False]*m for _ in range(n)]# 岛屿数量res = 0for i in range(n):for j in range(m):# 如果当前是陆地，且未被访问过，说明找到了一片新的陆地，标记该访问情况，深搜找这片的范围if grid[i][j] == 1 and not visited[i][j]:res += 1visited[i][j] = Truebfs(visited, grid, i, j) # dfs(visited, grid, i, j) 也可以print(res)卡码网100.岛屿的最大面积（深搜法；给前面这道题的基础上，遍历每片岛屿时，要记录每个陆地值得到岛屿面积）
点击查看代码
directions = [[1,0],[0,1],[-1,0],[0,-1]]
count = 0def dfs(visited, grid, x, y):global count # 设置全局变量for i,j in directions:cur_x = x + icur_y = y + jif cur_x<0 or cur_x>=len(grid) or cur_y<0 or cur_y>=len(grid[0]):continueif not visited[cur_x][cur_y] and grid[cur_x][cur_y]==1:visited[cur_x][cur_y] = Truecount += 1dfs(visited, grid, cur_x, cur_y)n, m = map(int, input().split())grid = []
for i in range(n):grid.append(list(map(int, input().split())))visited = [[False]*m for _ in range(n)]result = 0 # 记录count的最大值for i in range(n):for j in range(m):if grid[i][j]==1 and not visited[i][j]:count = 1visited[i][j] = Truedfs(visited, grid, i, j)result = max(result, count)print(result)PS:不想学习的一天，想念卡哥视频的一天，啥时候出图论啊
学的比较潦草，多复习
好冷，今天吃了好多美食，豆花牛肉、大盘鸡、凉皮、羊肉抓饭、冰淇淋，嗝~
让我们一起倒数十个数！
