棋盘游戏 HDU

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn = 1e4+5;
int G[105][105];
int a[maxn],b[maxn];
int match[105];
int st[105];
int n,m,ans;
bool find(int u) {
	for(int i = 1; i<=m; i++) {
		if(!st[i]&&G[u][i]) {
			st[i] = 1;
			if(!match[i]||find(match[i])) {
				match[i] = u;
				return true;
			}
		}
	}
	return false;
}
int Count() {
	int ans = 0;
	memset(match,0,sizeof(match));
	for(int i =0; i<=n; i++) {
		memset(st,0,sizeof(st));
		if(find(i)) 
			ans++;
	}
	return ans;
}
int main() {
	int k;
	int Case = 0;
	while(cin>>n>>m>>k) {
		memset(G,0,sizeof(G));
		for(int i = 0; i<k; i++) {
			cin>>a[i]>>b[i];
			G[a[i]][b[i]] = 1;
		}
		ans = 0;
		//先求最大匹配 
		int num = Count();
		//然后依次去掉每一条边，判断是不是会减少 
		for(int i =0; i<k; i++) {
			G[a[i]][b[i]] = 0;
			if(Count()<num) 
				ans++;
			G[a[i]][b[i]] = 1;
		}
		printf("Board %d have %d important blanks for %d chessmen.
",++Case,ans,num);
	}
}