206、【图论】岛屿数量

题目描述

代码

import collections

directions = [[0, 1], [0, -1], [1, 0], [-1, 0]]

def dfs(graph, visited, i, j):
    que = collections.deque()
    que.append([i, j])
    visited[i][j] = True

    while que:
        x, y = que.popleft()
        for move_x, move_y in directions:
            next_x, next_y = x + move_x, y + move_y
            if next_x >= n or next_x < 0 or next_y >= m or next_y < 0:
                continue
            if graph[next_x][next_y] == 1 and not visited[next_x][next_y]:
                visited[next_x][next_y] = True
                que.append([next_x, next_y])


if __name__ == '__main__':
    n, m = list(map(int, input().split()))
    graph = []
    for _ in range(n):
        graph.append(list(map(int, input().split())))
    visited = [[False] * m for _ in range(n)]

    res = 0
    for i in range(n):
        for j in range(m):
            if not visited[i][j] and graph[i][j] == 1:
                res += 1
                dfs(graph, visited, i, j)
    
    print(res)

参考文章：
岛屿数量·广搜版