1948B · Array Fix

Problem: You are given an integer array $a$ of length $n$.

You can perform the following operation any number of times (possibly zero): take any element of the array $a$, which is at least $10$, delete it, and instead insert the digits that element consisted of in the same position, in order they appear in that element.

For example:

• if we apply this operation to the $3$-rd element of the array $[12, 3, 45, 67]$, then the array becomes $[12, 3, 4, 5, 67]$.
• if we apply this operation to the $2$-nd element of the array $[2, 10]$, then the array becomes $[2, 1, 0]$.

Your task is to determine whether it is possible to make $a$ sorted in non-descending order using the aforementioned operation any number of times (possibly zero). In other words, you have to determine if it is possible to transform the array $a$ in such a way that $a_1 \le a_2 \le \dots \le a_k$, where $k$ is the current length of the array $a$.

Input Format: The first line contains a single integer $t$ ($1 \le t \le 10^3$) — the number of test cases.

Each test case consists of two lines:

• the first line contains a single integer $n$ ($2 \le n \le 50$).
• the second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($0 \le a_i \le 99$).

Output Format: For each test case, print YES if it is possible to make $a$ sorted in non-decreasing order using the aforementioned operation; otherwise, print NO.

You can print each letter in any case. For example, yes, Yes, YeS will all be recognized as a positive answer.

Note: In the first example, you can split the first element, then the array becomes $[1, 2, 3, 45, 67]$.

In the second example, there is no way to get a sorted array.

In the third example, the array is already sorted.