日常水题-bfs求细胞数量

Posted 2021-01-08 hwjia

 P1451 求细胞数量

一题让我学会bfs系列qaq

 1 #include<cstdio>
 2 #include<iostream>
 3 using namespace std;
 4 const int sz = 110;
 5 int n, m, ans = 0;
 6 int dx[4]={0,1,0,-1};
 7 int dy[4]={1,0,-1,0};
 8 int plat[sz][sz];
 9 int q[sz][3];
10 struct node {
11     int x, y;
12 };
13 void bfs(int x,int y) {
14     int head = 1, tail = 1, mx, my;
15     plat[x][y] = 0;
16     q[1][1] = x, q[1][2] = y;
17     while(head<=tail) {
18         for(int i = 0; i < 4; i++) {
19             mx = q[head][1] + dx[i];
20             my = q[head][2] + dy[i];
21             if(mx>=1&&my>=1&&mx<=n&&my<=m&&plat[mx][my]) {
22                 tail++;
23                 q[tail][1] = mx;
24                 q[tail][2] = my;
25                 plat[mx][my] = 0;
26             }
27         }
28         head++;
29     }
30 }
31 int main() {
32     scanf("%d%d",&n,&m);
33     for(int i = 1; i <= n; i++) {
34         for(int j = 1; j <= m; j++) 
35             scanf("%1d",&plat[i][j]);
36     }
37     for(int i = 1; i <= n; i++) {
38         for(int j = 1; j <= m; j++) {
39             if(plat[i][j]) {
40                 bfs(i,j);
41                 ans++;
42             }
43         }
44     }
45     printf("%d",ans);
46     return 0;
47 }

 

　　不那样读入一行就算一个了qaq

我写的博客过两天自己都看不懂QAQ