Search for Indices with Given Difference and Distance

You are provided with an array containing 'N' non-negative integers, along with two other non-negative integers 'K' and 'M'. Your task is to identify and return a pair of indices (i, j) from the array such that 'i' ≠ 'j', |Ai - Aj| ≤ 'M', and |i - j| ≤ 'K', where |a - b| denotes the absolute value of the difference between a and b.

Input:

The input starts with an integer 'T', representing the number of test cases.
For each test case, the first line contains three space-separated integers 'N', 'K', and 'M'.
The second line includes 'N' space-separated integers representing the elements of the array.

Output:

A function that returns a pair of indices (i, j). The output will display “valid” if the indices satisfy the conditions, otherwise it will show “invalid”.

Example:

Input:
  T = 1
  N = 5 K = 2 M = 3
  Array = [1, 3, 6, 7, 3]
  
Output:
 “valid”

Constraints:

• 1 ≤ T ≤ 50
• 2 ≤ N ≤ 10⁴
• 1 ≤ K ≤ N
• 1 ≤ M ≤ 10⁹
• 1 ≤ ARR[i] ≤ 10⁹
• The array is 0-indexed, with 0 ≤ i, j < N.

Note:

No need to print any output, just implement the function based on the conditions provided. It is guaranteed that at least one valid pair of indices exists.