思想：遍历到为1的节点，再搜索标记，每遇到新的陆地节点，增加计数

• 深度搜索
• 广度搜索：此处用 [] 作为待遍历队列也可，que（append，popleft）

import collections

def dfs(grid, visited, x, y):
    dirs = [[0, 1], [0, -1], [1, 0], [-1, 0]]
    for add_x, add_y in dirs:
        next_x = x + add_x
        next_y = y + add_y
        
        if next_x < 0 or next_x >= len(grid) or next_y < 0 or next_y >= len(grid[0]):
            continue
        
        if not visited[next_x][next_y] and grid[next_x][next_y]:
            visited[next_x][next_y] = True
            dfs(grid, visited, next_x, next_y)

def bfs(grid, visited, x, y):
    dirs = [[0, 1], [0, -1], [1, 0], [-1, 0]]
    que = collections.deque()
    # que = []
    que.append([x, y])
    visited[x][y] = True
    while que:
        # cur = que.pop()
        cur = que.popleft()
        cur_x = cur[0]
        cur_y = cur[1]
        for add_x, add_y in dirs:
            next_x = cur_x + add_x
            next_y = cur_y + add_y
        
            if next_x < 0 or next_x >= len(grid) or next_y < 0 or next_y >= len(grid[0]):
                continue
        
            if not visited[next_x][next_y] and grid[next_x][next_y]:
                que.append([next_x, next_y])
                visited[next_x][next_y] = True
        
        

tmp = list(map(int, input().split()))
m, n = tmp[0], tmp[1]

grid = [[0]*n for _ in range(m)]
visited = [[False]*n for _ in range(m)]
for i in range(m):
    tmp = list(map(int, input().split()))
    for j in range(n):
        grid[i][j] = tmp[j]

result = 0
for i in range(m):
    for j in range(n):
        if not visited[i][j] and grid[i][j]:
            visited[i][j] = True
            result += 1
            bfs(grid, visited, i, j)

print(result)