CodeTON Round 4 (Div. 1 + Div. 2, Rated, Prizes!)
E
Monsters
Codeforces
2100
原题
← DF →
翻译中…

There is an undirected graph with $n$ vertices and $m$ edges. Initially, for each vertex $i$, there is a monster with danger $a_{i}$ on that vertex. For a monster with danger $a_{i}$, you can defeat it if and only if you have defeated at least $a_{i}$ other monsters before.

翻译中…

Now you want to defeat all the monsters. First, you choose some vertex $s$ and defeat the monster on that vertex (since you haven't defeated any monsters before, $a_{s}$ has to be $0$). Then, you can move through the edges. If you want to move from vertex $u$ to vertex $v$, then the following must hold: either the monster on vertex $v$ has been defeated before, or you can defeat it now. For the second case, you defeat the monster on vertex $v$ and reach vertex $v$.

翻译中…

You can pass the vertices and the edges any number of times. Determine whether you can defeat all the monsters or not.

翻译中…

Input

翻译中…

Each test contains multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 10^4$) — the number of test cases. Their description follows.

翻译中…

The first line of each test case contains two integers $n$, $m$ ($1 \le n, m \le 2 \cdot 10^5$) — the number of vertices and edges in the graph respectively.

翻译中…

The second line of each test case contains $n$ integers $a_{1}, a_{2}, \ldots, a_{n}$ ($0 \le a_{i} \le n$) — the dangers of monsters on corresponding vertices.

翻译中…

For the following $m$ lines, each line contains two integers $u$, $v$ ($1 \le u, v \le n$), describing an edge connecting vertex $u$ and vertex $v$. It is guaranteed that there are no multi-edges or self-loops in the graph.

翻译中…

It is guaranteed that both the sum of $n$ and the sum of $m$ over all test cases do not exceed $2 \cdot 10^5$.

翻译中…

Output

翻译中…

For each test case, output "YES" if you can defeat all the monsters, or "NO" otherwise.

翻译中…

You can output the answer in any case (upper or lower). For example, the strings "yEs", "yes", "Yes", and "YES" will be recognized as positive responses.

翻译中…

Note

翻译中…

In the first test case, you can start at vertex $3$ and defeat the monster on it, before you go to vertices $2$, $1$ in this order, defeating the monsters on them as well. Then you return to vertex $3$, and go to vertex $4$, defeating the monster on it.

翻译中…

In the third test case, there is no path to vertex $4$ if you start at vertex $1$. Also, there is no path to vertices $1$, $2$, and $3$ if you start at vertex $4$.

翻译中…

样例

Input #1
5
4 3
2 1 0 3
1 2
2 3
3 4
6 6
0 1 2 3 0 1
1 2
2 3
3 4
4 5
4 6
5 6
4 3
0 1 2 0
1 2
2 3
1 3
4 6
1 1 1 0
1 2
3 2
4 3
2 4
4 1
1 3
5 5
0 1 3 2 0
1 2
2 3
3 4
4 5
3 5
Output #1
YES
YES
NO
YES
NO
InputCopy OutputCopy
题目信息
题号
1810E
时间限制
2 s
内存限制
256 MB
标签
暴力
数据结构
DFS 及类似
并查集
图论
贪心

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。