Codeforces Round 794 (Div. 2) |
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Finished |
You are given an array of $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$. After you watched the amazing film "Everything Everywhere All At Once", you came up with the following operation.
In one operation, you choose $$$n-1$$$ elements of the array and replace each of them with their arithmetic mean (which doesn't have to be an integer). For example, from the array $$$[1, 2, 3, 1]$$$ we can get the array $$$[2, 2, 2, 1]$$$, if we choose the first three elements, or we can get the array $$$[\frac{4}{3}, \frac{4}{3}, 3, \frac{4}{3}]$$$, if we choose all elements except the third.
Is it possible to make all elements of the array equal by performing a finite number of such operations?
The first line of the input contains a single integer $$$t$$$ ($$$1 \le t \le 200$$$) — the number of test cases. The description of the test cases follows.
The first line of each test case contains a single integer $$$n$$$ ($$$3 \le n \le 50$$$) — the number of integers.
The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$0 \le a_i \le 100$$$).
For each test case, if it is possible to make all elements equal after some number of operations, output $$$\texttt{YES}$$$. Otherwise, output $$$\texttt{NO}$$$.
You can output $$$\texttt{YES}$$$ and $$$\texttt{NO}$$$ in any case (for example, strings $$$\texttt{yEs}$$$, $$$\texttt{yes}$$$, $$$\texttt{Yes}$$$ will be recognized as a positive response).
4342 42 4251 2 3 4 544 3 2 1324 2 22
YES YES NO NO
In the first test case, all elements are already equal.
In the second test case, you can choose all elements except the third, their average is $$$\frac{1 + 2 + 4 + 5}{4} = 3$$$, so the array will become $$$[3, 3, 3, 3, 3]$$$.
It's possible to show that it's impossible to make all elements equal in the third and fourth test cases.
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