带权二分图匹配（KM模板）

1.  最大权二分匹配
2. 最小权二分匹配 （建边时，把边改成负的）

#include<iostream>
#include<cstring>
#include<stdio.h>
#include<math.h>
#include<algorithm>
#include<queue>
#include<vector>
using namespace std;
const int maxn = 505;
const int INF = 0x3f3f3f3f;
int G[maxn + 5][maxn + 5];
int ex_X[maxn], ex_Y[maxn];
bool vis_X[maxn], vis_Y[maxn];
int Slack[maxn + 5];
int Match[maxn + 5];
int N;
bool Dfs(int x){
	vis_X[x] = 1;
	for(int i = 1; i <= N; ++i){
		if(vis_Y[i]) continue;
		int tmp = ex_X[x] + ex_Y[i] - G[x][i];
		if(tmp != 0){
			Slack[i] = min (Slack[i], tmp);
		} else {
			vis_Y[i] = 1;
			if (Match[i] == -1 || Dfs(Match[i])) {
				Match[i] = x;
				return true;
			}
		}
	}
	return false;
}
/*
2 
100 10
15 23
*/
 
int KM(){
	memset(Match, -1, sizeof(Match));	
	memset(ex_X, 0, sizeof(ex_X));
	memset(ex_Y, 0, sizeof(ex_Y));
	
	for (int i = 1; i <= N; ++i) {
		for (int j = 1; j <= N; ++j) {
			ex_X[i] = max(ex_X[i], G[i][j]);
		}
	}
	for (int i = 1; i <= N; ++i) {
		memset(Slack, INF, sizeof Slack);
		while(1){
			memset(vis_X, 0, sizeof(vis_X));
			memset(vis_Y, 0, sizeof(vis_Y));
			if (Dfs(i)) break;
			int tmp = INF;
			for (int j = 1; j <= N; ++j) {
				if( vis_Y[j] == 0 )
					tmp = min(tmp, Slack[j]); 
			}
			if(tmp == INF) return -1;
			for(int j = 1; j <= N; ++j) {
				if(vis_X[j]) ex_X[j] -= tmp; 
				if(vis_Y[j]) ex_Y[j] += tmp;
				else Slack[j] -= tmp;
			}
		}
	}
	int Ans = 0;
	for(int i = 1; i <= N; i++){
		if(Match[i] != -1)
			Ans += G[Match[i]][i];
	}
	return Ans;
}
int main (){
	while(~scanf("%d", &N)){
		int Temp;
		for(int i = 1; i <= N; ++i){
			for(int j = 1; j <= N; ++j){
				scanf("%d", &G[i][j]);
			}
		}
		printf("%d\n", KM());
	}
	return 0;
}