Merge pull request #2686 from numberoustar/master

订正文件0099.岛屿的数量广搜.md文件，python部分用的是深搜算法

Author: youngyangyang04

problems/kamacoder/0099.岛屿的数量广搜.md

@@ -246,29 +246,36 @@ public class Main {
 
 ```python
 
-def dfs(grid, visited, x, y):
-    dir = [(0, 1), (1, 0), (-1, 0), (0, -1)]  # 四个方向
-    for d in dir:
-        nextx, nexty = x + d[0], y + d[1]
-        if 0 <= nextx < len(grid) and 0 <= nexty < len(grid[0]):
-            if not visited[nextx][nexty] and grid[nextx][nexty] == 1:  # 没有访问过的 同时 是陆地的
-                visited[nextx][nexty] = True
-                dfs(grid, visited, nextx, nexty)
+from collections import deque
+directions = [[0, 1], [1, 0], [0, -1], [-1, 0]]
+def bfs(grid, visited, x, y):
+    que = deque([])
+    que.append([x,y])
+    while que:
+        cur_x, cur_y = que.popleft()
+        for i, j in directions:
+            next_x = cur_x + i
+            next_y = cur_y + j
+            if next_y < 0 or next_x < 0 or next_x >= len(grid) or next_y >= len(grid[0]):
+                continue
+            if not visited[next_x][next_y] and grid[next_x][next_y] == 1: 
+                visited[next_x][next_y] = True
+                que.append([next_x, next_y])
+
 
 def main():
     n, m = map(int, input().split())
-    grid = [list(map(int, input().split())) for _ in range(n)]
+    grid = []
+    for i in range(n):
+        grid.append(list(map(int, input().split())))
     visited = [[False] * m for _ in range(n)]
-
-    result = 0
+    res = 0
     for i in range(n):
         for j in range(m):
-            if not visited[i][j] and grid[i][j] == 1:
-                visited[i][j] = True
-                result += 1  # 遇到没访问过的陆地，+1
-                dfs(grid, visited, i, j)  # 将与其链接的陆地都标记上 True
-
-    print(result)
+            if grid[i][j] == 1 and not visited[i][j]:
+                res += 1
+                bfs(grid, visited, i, j)
+    print(res)
 
 if __name__ == "__main__":
     main()