CF1436A.Reorder

普及/提高-

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题目描述

For a given array aa consisting of nn integers and a given integer mm find if it is possible to reorder elements of the array aa in such a way that i=1nj=inajj\sum_{i=1}^{n}{\sum_{j=i}^{n}{\frac{a_j}{j}}} equals mm ? It is forbidden to delete elements as well as insert new elements. Please note that no rounding occurs during division, for example, 52=2.5\frac{5}{2}=2.5 .

输入格式

The first line contains a single integer tt — the number of test cases ( 1t1001 \le t \le 100 ). The test cases follow, each in two lines.

The first line of a test case contains two integers nn and mm ( 1n1001 \le n \le 100 , 0m1060 \le m \le 10^6 ). The second line contains integers a1,a2,,ana_1, a_2, \ldots, a_n ( 0ai1060 \le a_i \le 10^6 ) — the elements of the array.

输出格式

For each test case print "YES", if it is possible to reorder the elements of the array in such a way that the given formula gives the given value, and "NO" otherwise.

输入输出样例

  • 输入#1

    2
    3 8
    2 5 1
    4 4
    0 1 2 3

    输出#1

    YES
    NO

说明/提示

In the first test case one of the reorders could be [1,2,5][1, 2, 5] . The sum is equal to (11+22+53)+(22+53)+(53)=8(\frac{1}{1} + \frac{2}{2} + \frac{5}{3}) + (\frac{2}{2} + \frac{5}{3}) + (\frac{5}{3}) = 8 . The brackets denote the inner sum j=inajj\sum_{j=i}^{n}{\frac{a_j}{j}} , while the summation of brackets corresponds to the sum over ii .

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