hdu2255 奔小康赚大钱 KM 算法

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int n, a[305][305], mat[305], exu[305], exv[305], qiw[305];
const int oo=0x3f3f3f3f;
bool viu[305], viv[305];
bool dfs(int x){
    viu[x] = true;
    for(int i=1; i<=n; i++){
        if(viv[i])  continue;
        int gap=exu[x]+exv[i]-a[x][i];
        if(!gap){
            viv[i] = true;
            if(!mat[i] || dfs(mat[i])){
                mat[i] = x;
                return true;
            }
        }
        else qiw[i] = min(qiw[i], gap);
    }
    return false;
}
int main(){
    while(scanf("%d", &n)!=EOF){
        for(int i=1; i<=n; i++)
            for(int j=1; j<=n; j++)
                scanf("%d", &a[i][j]);
        memset(mat, 0, sizeof(mat));
        memset(exu, 0, sizeof(exu));
        memset(exv, 0, sizeof(exv));
        for(int i=1; i<=n; i++)
            for(int j=1; j<=n; j++)
                exu[i] = max(exu[i], a[i][j]);
        for(int i=1; i<=n; i++){
            memset(qiw, 0x3f, sizeof(qiw));
            while(true){
                memset(viu, 0, sizeof(viu));
                memset(viv, 0, sizeof(viv));
                if(dfs(i))  break;
                int tmp=oo;
                for(int j=1; j<=n; j++)
                    if(!viv[j])
                        tmp = min(tmp, qiw[j]);
                for(int j=1; j<=n; j++){
                    if(viu[j])  exu[j] -= tmp;
                    if(viv[j])  exv[j] += tmp;
                    else    qiw[j] -= tmp;
                }
            }
        }
        int ans=0;
        for(int i=1; i<=n; i++)
            ans += a[mat[i]][i];
        printf("%d\n", ans);
    }
    return 0;
}