CF1736B.Playing with GCD

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题目描述

You are given an integer array aa of length nn .

Does there exist an array bb consisting of n+1n+1 positive integers such that ai=gcd(bi,bi+1)a_i=\gcd (b_i,b_{i+1}) for all ii ( 1in1 \leq i \leq n )?

Note that gcd(x,y)\gcd(x, y) denotes the greatest common divisor (GCD) of integers xx and yy .

输入格式

Each test contains multiple test cases. The first line contains the number of test cases tt ( 1t1051 \leq t \leq 10^5 ). Description of the test cases follows.

The first line of each test case contains an integer nn ( 1n1051 \leq n \leq 10^5 ) — the length of the array aa .

The second line of each test case contains nn space-separated integers a1,a2,,ana_1,a_2,\ldots,a_n representing the array aa ( 1ai1041 \leq a_i \leq 10^4 ).

It is guaranteed that the sum of nn over all test cases does not exceed 10510^5 .

输出格式

For each test case, output "YES" if such bb exists, otherwise output "NO". You can print each letter in any case (upper or lower).

输入输出样例

  • 输入#1

    4
    1
    343
    2
    4 2
    3
    4 2 4
    4
    1 1 1 1

    输出#1

    YES
    YES
    NO
    YES

说明/提示

In the first test case, we can take b=[343,343]b=[343,343] .

In the second test case, one possibility for bb is b=[12,8,6]b=[12,8,6] .

In the third test case, it can be proved that there does not exist any array bb that fulfills all the conditions.

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