Array conversion

4.2

10 votes
Problem

You are given an array Arr containing N numbers and an integer K. You can implement the following operations on this array:

  • Replace an element Arr[i] with -Arr[i]
  • Replace an element Arr[i] with Arr[i] + i
  • Replace an element Arr[i] with Arr[i] - i

You cannot perform more than one operation per element of the array.

Write a program to determine whether it is possible to make the sum of all the elements in the array Arr equal to K.

Input format

  • First line: T (number of test cases)
  • First line in each test case: Two space-separated integers N and K
  • Second line in each test case: N space-separated integers (denoting the array Arr)

Output format

For each test case, print YES or NO depending on the result.

Constraints

1T50
1N100
1K10000
0Arri100

Time Limit: 1
Memory Limit: 256
Source Limit:
Explanation

For testcase 2 if we change the given array {1,2,3,4} to {-1,4,6,-4}

By applying transformation 1 to element 1 and 4 making them 1->-1 and 4->-4
Transformation 2 to element 2 and 3 making them 2->2+2 and 3->3+3
then the sum of all the elements will be 5.

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