Description

Input

Output

Sample Input

Sample Output

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#define mem(_, __) memset(_, __, sizeof(_));
const int maxn = 111;

using namespace std;

int a[maxn], T, n, x, y;
bool flag, vis[maxn][maxn], v[maxn];

void DFS(int x, int sum)
{
    if (sum == n - 1)
    {
        return ;
    }
    for (int i = 1; i <= n; i ++)
    {
        if (i == x)
            continue;
        // 已經走過了
        if (v[i] == 1)
            continue;
        // 不存在從x到i的邊
        if (vis[x][i] == 0)
            continue;
        // 有一條邊不滿足條件，即父節點的權值小於等於任意子節點的權值，所以直接終止查詢
        if (a[x] > a[i])
        {
            flag = true;
            return;
        }

        v[i] = 1;// 標記當前節點
        DFS(i, sum + 1);
        if (flag)
            return;
    }
}

int main()
{
    scanf("%d", &T);
    while (T --)
    {
        scanf("%d", &n);
        for (int i = 1; i <= n; i ++)
            scanf("%d", &a[i]);
        mem(vis, 0);
        // n - 1 條邊
        for (int i = 1; i < n; i ++)
        {
            scanf("%d%d", &x, &y);
            vis[x][y] = vis[y][x] = 1;
        }
        flag = false;
        mem(v, 0);
        v[1] = 1;
        DFS(1, 0);
        if (flag)
            cout << "No" << endl;
        else
            cout << "Yes" << endl;
    }
    return 0;
}