[数据结构与算法]P1451 求细胞数量

求细胞数量 - 洛谷

/*
 * @Description: To iterate is human, to recurse divine.
 * @Autor: Recursion
 * @Date: 2022-04-05 20:25:15
 * @LastEditTime: 2022-04-05 20:31:43
 */
#include <bits/stdc++.h>
#define LL long long 
using namespace std;
const int maxn = 1e6 + 10;
const int mod = 1e9 + 7;
const int INF = 1e9 + 10;
const int N = 1e4;
char a[N][N];
int n,m,ans;
int dx[4] = {0,1,-1,0};
int dy[4] = {1,0,0,-1};
void dfs(int x,int y)
{
    a[x][y] = '0';
    for(int i = 0;i < 4;i ++)
        for(int j = 0;j < 4;j ++){
            int tx = x + dx[i];
            int ty = y + dy[i];
            if(tx>0&&tx<=n&&ty>0&&ty<=m&&a[tx][ty]!='0')
                dfs(tx,ty);
        }
}

int main()
{
    ios::sync_with_stdio(false);
    cin >> n >> m;
    for(int i = 1;i <= n;i ++)
        for(int j = 1;j <= m;j ++)
            cin >> a[i][j];
    for(int i = 1;i <= n;i ++)
        for(int j = 1;j <= m;j ++){
            if(a[i][j] != '0'){
                dfs(i,j);
                ans++;
            }
        }
    cout << ans << endl;
            // cout << a[i][j];
    return 0;
}