poj1469

二分图匹配，匈牙利算法

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define maxn 505

int uN, vN;
bool g[maxn][maxn];
int xM[maxn], yM[maxn];
bool chk[maxn];
int n, p;

void input()
{
    int a, m;
    memset(g, 0, sizeof(g));
    for (int i = 0; i < p; i++)
    {
        scanf("%d", &m);
        for (int j = 0; j < m; j++)
        {
            scanf("%d", &a);
            a--;
            g[i][a] = true;
        }
    }
}

bool SearchPath(int u)
{
    int v;
    for (v = 0; v < vN; v++)
        if (g[u][v] && !chk[v])
        {
            chk[v] = true;
            if (yM[v] == -1 || SearchPath(yM[v]))
            {
                yM[v] = u;
                xM[u] = v;
                return true;
            }
        }
    return false;
}

int MaxMatch()
{
    int u, ret = 0;
    memset(xM, -1, sizeof(xM));
    memset(yM, -1, sizeof(yM));
    for (u = 0; u < uN; u++)
        if (xM[u] == -1)
        {
            memset(chk, false, sizeof(chk));
            if (SearchPath(u))
                ret++;
        }
    return ret;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while (t--)
    {
        scanf("%d%d", &p, &n);
        input();
        uN = p;
        vN = n;
        int ans = MaxMatch();
        if (ans == p)
            printf("YES\n");
        else
            printf("NO\n");
    }
    return 0;
}