poj1330

简单题

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

#define maxn 10005

bool vis[maxn];
int father[maxn];

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while (t--)
    {
        memset(father, -1, sizeof(father));
        memset(vis, 0, sizeof(vis));
        int n;
        scanf("%d", &n);
        int a, b;
        for (int i = 0; i < n - 1; i++)
        {
            scanf("%d%d", &a, &b);
            father[b] = a;
        }
        scanf("%d%d", &a, &b);
        while (b != -1)
        {
            vis[b] = true;
            b = father[b];
        }
        while (!vis[a])
            a = father[a];
        printf("%d\n", a);
    }
    return 0;
}