P3386 模板二分图匹配

Posted 2020-11-28 xcfxcf

https://www.luogu.com.cn/problem/P3386

 

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e3 + 10;
int n,m,e,link[maxn][maxn],ans;
int used[maxn],girl[maxn];
int find(int x){
    for(int j = 1; j <= m; j++){
        //used[j]=1说明有标记，试图改变这个妹子归属问题但是没有成功
        if(link[x][j] && !used[j]) {
            used[j] = 1;
            if (!girl[j] || find(girl[j])) {
                //名花无主或者能腾出地方来
                girl[j] = x;
                return 1;
            }
        }
    }
    return 0;
}
int main(){
    ios::sync_with_stdio(0);
    cin >> n >> m >> e;
    for(int i = 0; i < e; i++){
        int u,v;
        cin >> u >> v;
        if(u > n || v > m)
            continue;
        link[u][v] = 1;
    }
    for(int i = 1; i <= n; i++){
        memset(used,0, sizeof(used));
        if(find(i))
            ans++;
    }
    cout << ans;
    return 0;
}

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匈牙利算法，即由增广路求最大匹配

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https://blog.csdn.net/dark_scope/article/details/8880547