CF1741E.Sending a Sequence Over the Network

The sequence $a$ is sent over the network as follows:

1. sequence $a$ is split into segments (each element of the sequence belongs to exactly one segment, each segment is a group of consecutive elements of sequence);
2. for each segment, its length is written next to it, either to the left of it or to the right of it;
3. the resulting sequence $b$ is sent over the network.

For example, we needed to send the sequence $a = [1, 2, 3, 1, 2, 3]$. Suppose it was split into segments as follows: $[\color{red}{1}] + [\color{blue}{2, 3, 1}] + [\color{green}{2, 3}]$. Then we could have the following sequences:

• $b = [1, \color{red}{1}, 3, \color{blue}{2, 3, 1}, \color{green}{2, 3}, 2]$,
• $b = [\color{red}{1}, 1, 3, \color{blue}{2, 3, 1}, 2, \color{green}{2, 3}]$,
• $b = [\color{red}{1}, 1, \color{blue}{2, 3, 1}, 3, 2, \color{green}{2, 3}]$,
• $b = [\color{red}{1}, 1,\color{blue}{2, 3, 1}, 3, \color{green}{2, 3}, 2]$.

If a different segmentation had been used, the sent sequence might have been different.

The sequence $b$ is given. Could the sequence $b$ be sent over the network? In other words, is there such a sequence $a$ that converting $a$ to send it over the network could result in a sequence $b$?

序列 $a$ 通过网络传输的方式如下：

1. 将序列 $a$ 划分为若干段（序列中的每个元素恰好属于一段，每段均由序列中连续的若干元素组成）；
2. 对每一段，在该段的左侧或右侧紧邻位置写上其长度；
3. 将由此得到的序列 $b$ 通过网络发送。

例如，我们需要发送序列 $a = [1, 2, 3, 1, 2, 3]$。假设将其划分为如下几段：$[\color{red}{1}] + [\color{blue}{2, 3, 1}] + [\color{green}{2, 3}]$。那么可能得到以下几种序列 $b$：

• $b = [1, \color{red}{1}, 3, \color{blue}{2, 3, 1}, \color{green}{2, 3}, 2]$,
• $b = [\color{red}{1}, 1, 3, \color{blue}{2, 3, 1}, 2, \color{green}{2, 3}]$,
• $b = [\color{red}{1}, 1, \color{blue}{2, 3, 1}, 3, 2, \color{green}{2, 3}]$,
• $b = [\color{red}{1}, 1,\color{blue}{2, 3, 1}, 3, \color{green}{2, 3}, 2]$。

若采用不同的分段方式，则发送的序列也可能不同。

现给定序列 $b$。该序列 $b$ 是否可能是通过上述网络传输方式发送的？换言之，是否存在某个序列 $a$，使得将 $a$ 按照上述规则转换后，恰好得到序列 $b$？

The first line of input data contains a single integer $t$ ($1 \le t \le 10^4$) — the number of test cases.

Each test case consists of two lines.

The first line of the test case contains an integer $n$ ($1 \le n \le 2 \cdot 10^5$) — the size of the sequence $b$.

The second line of test case contains $n$ integers $b_1, b_2, \dots, b_n$ ($1 \le b_i \le 10^9$) — the sequence $b$ itself.

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

输入数据的第一行包含一个整数 $t$（$1 \le t \le 10^4$）—— 测试用例的数量。

每个测试用例由两行组成。

测试用例的第一行包含一个整数 $n$（$1 \le n \le 2 \cdot 10^5$）—— 序列 $b$ 的长度。

测试用例的第二行包含 $n$ 个整数 $b_1, b_2, \dots, b_n$（$1 \le b_i \le 10^9$）—— 序列 $b$ 本身。

保证所有测试用例的 $n$ 值之和不超过 $2 \cdot 10^5$。

For each test case print on a separate line:

• YES if sequence $b$ could be sent over the network, that is, if sequence $b$ could be obtained from some sequence $a$ to send $a$ over the network.
• NO otherwise.

You can output YES and NO in any case (for example, strings yEs, yes, Yes and YES will be recognized as positive response).

对于每个测试用例，在单独一行中输出：

• 若序列 $b$ 可能被发送至网络（即：存在某个序列 $a$，使得将 $a$ 发送至网络后可得到序列 $b$），则输出 YES；
• 否则输出 NO。

YES 和 NO 的大小写不限（例如，字符串 yEs、yes、Yes 和 YES 均被视为肯定回答）。

In the first case, the sequence $b$ could be obtained from the sequence $a = [1, 2, 3, 1, 2, 3]$ with the following partition: $[\color{red}{1}] + [\color{blue}{2, 3, 1}] + [\color{green}{2, 3}]$. The sequence $b$: $[\color{red}{1}, 1, \color{blue}{2, 3, 1}, 3, 2, \color{green}{2, 3}]$.

In the second case, the sequence $b$ could be obtained from the sequence $a = [12, 7, 5]$ with the following partition: $[\color{red}{12}] + [\color{green}{7, 5}]$. The sequence $b$: $[\color{red}{12}, 1, 2, \color{green}{7, 5}]$.

In the third case, the sequence $b$ could be obtained from the sequence $a = [7, 8, 9, 10, 3]$ with the following partition: $[\color{red}{7, 8, 9, 10, 3}]$. The sequence $b$: $[5, \color{red}{7, 8, 9, 10, 3}]$.

In the fourth case, there is no sequence $a$ such that changing $a$ for transmission over the network could produce a sequence $b$.

在第一种情况下，序列 $b$ 可由序列 $a = [1, 2, 3, 1, 2, 3]$ 经如下划分得到：$[\color{red}{1}] + [\color{blue}{2, 3, 1}] + [\color{green}{2, 3}]$。所得序列 $b$ 为：$[\color{red}{1}, 1, \color{blue}{2, 3, 1}, 3, 2, \color{green}{2, 3}]$。

在第二种情况下，序列 $b$ 可由序列 $a = [12, 7, 5]$ 经如下划分得到：$[\color{red}{12}] + [\color{green}{7, 5}]$。所得序列 $b$ 为：$[\color{red}{12}, 1, 2, \color{green}{7, 5}]$。

在第三种情况下，序列 $b$ 可由序列 $a = [7, 8, 9, 10, 3]$ 经如下划分得到：$[\color{red}{7, 8, 9, 10, 3}]$。所得序列 $b$ 为：$[5, \color{red}{7, 8, 9, 10, 3}]$。

在第四种情况下，不存在序列 $a$，使得对 $a$ 进行网络传输时的变换能生成序列 $b$。