B'You are given an array a of n positive integers. You can use the following operation as many times as you like: select any integer 1 <= k <= n and do one of two things: For example, if n=5 and a=[3,2,2,1,4] , then you can apply one of the following operations to it (not all possible options are listed below): Determine if it is possible to make all the elements of the array equal to zero by applying a certain number of operations. The first line contains one positive integer t ( 1 <= t <= 30000 ) -- the number of test cases. Then t test cases follow. Each test case begins with a line containing one integer n ( 1 <= n <= 30000 ) -- the number of elements in the array. The second line of each test case contains n integers a_1 ldots a_n ( 1 <= a_i <= 10^6 ). The sum of n over all test cases does not exceed 30000 . For each test case, output on a separate line: The letters in the words YES and NO can be outputed in any case. '...