题目描述
You are given an array of integers $a_1, a_2, \ldots, a_n$. In one operation, you do the following:
- Choose a non-negative integer $m$, such that $2^m \leq n$.
- Subtract $1$ from $a_i$ for all integers $i$, such that $1 \leq i \leq 2^m$.
Can you sort the array in non-decreasing order by performing some number (possibly zero) of operations?
An array is considered non-decreasing if $a_i \leq a_{i + 1}$ for all integers $i$ such that $1 \leq i \leq n - 1$.
Input
The first line contains a single integer $t$ ($1 \leq t \leq 10^4$) — the number of test cases. The description of the test cases follows.
The first line of each test case contains a single integer $n$ ($1 \leq n \leq 20$) — the length of array $a$.
The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ — the integers in array $a$ ($0 \leq a_i \leq 1000$).
Output
For each test case, output "YES" if the array can be sorted, and "NO" otherwise.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first test case, the array is already sorted in non-decreasing order, so we don't have to perform any operations.
In the second test case, we can choose $m = 1$ twice to get the array $[4, 3, 3, 4, 4]$. Then, we can choose $m = 0$ once and get the sorted in non-decreasing order array $[3, 3, 3, 4, 4]$.
In the third test case, we can choose $m = 0$ once and get the array $[5, 5, 5, 7, 5, 6, 6, 8, 7]$. Then, we can choose $m = 2$ twice and get the array $[3, 3, 3, 5, 5, 6, 6, 8, 7]$. After that, we can choose $m = 3$ once and get the sorted in non-decreasing order array $[2, 2, 2, 4, 4, 5, 5, 7, 7]$.
For the fourth and fifth test case, it can be shown that the array could not be sorted using these operations.