[ZJOI2007] 矩阵游戏

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int tot,n,t,dep[600],q[600],cur[600],h[600],S,T;

struct edge{
	int to,nxt,z;
}e[100000];
void add(int x,int y,int z)
{
	e[++tot] = edge{y,h[x],z},h[x] = tot;
	e[++tot] = edge{x,h[y],0},h[y] = tot;
}
int bfs()
{
	for (int i = 0; i <= 2 * n + 2; i++) cur[i] = h[i];
	memset(dep,0,sizeof dep);
	int head = 0,tail = 1;
	q[1] = S,dep[S] = 1;
	while (head < tail)
	{
		int u = q[++head];
		for (int i = h[u]; i; i = e[i].nxt)
		{
			int v = e[i].to;
			if (dep[v] || e[i].z <= 0) continue;
			dep[v] = dep[u] + 1,q[++tail] = v;
		}
	}
	return dep[T];
}
int dinic(int u,int mn,int fa)
{
	if (u == T || mn <= 0) return mn;
	int flow = 0,sum = 0;
	for (int i = cur[u]; i; i = e[i].nxt)
	{
		int v = e[i].to; cur[u] = i;
		if (v == fa || e[i].z <= 0 || dep[v] != dep[u] + 1) continue;
		sum = dinic(v,min(mn,e[i].z),u);
		if (sum <= 0) continue;
		flow += sum,e[i].z -= sum,e[i ^ 1].z += sum,mn -= sum;
		if (mn <= 0) break;
	}
	return flow;
}
int main()
{
	scanf("%d",&t);
	for (; t; t--)
	{
		memset(h,0,sizeof h),tot = 1;
		scanf("%d",&n);
		S = 2 * n + 1,T = 2 * n + 2;
		for (int i = 1; i <= n; i++)
			for (int j = 1,q; j <= n; j++)
			{
				scanf("%d",&q);
				if (q) add(i,j + n,1);
			}
		for (int i = 1; i <= n; i++) add(S,i,1),add(i + n,T,1);
		int ans = 0;
		while (bfs())
			ans += dinic(S,10000,S);
		if (ans == n) printf("Yes\n");
		else printf("No\n");
	}
}