Equal

Given an array A of N integers, find the index of values that satisfy P + Q = R + S, where P, Q, R & S are integers values in the array

Expected time complexity O(N²)

NOTE:
1) Return the indices A1 B1 C1 D1, so that 
  A[A1] + A[B1] = A[C1] + A[D1]
  A1 < B1, C1 < D1
  A1 < C1, B1 != D1, B1 != C1 
2) If there are more than one solutions,
   then return the tuple of values which are lexicographical smallest. 

Assume we have two solutions
S1 : A1 B1 C1 D1 ( these are values of indices in the array )
S2 : A2 B2 C2 D2

S1 is lexicographically smaller than S2 if:
  A1 < A2 OR
  A1 = A2 AND B1 < B2 OR
  A1 = A2 AND B1 = B2 AND C1 < C2 OR 
  A1 = A2 AND B1 = B2 AND C1 = C2 AND D1 < D2

1 <= N <= 1000

0 <= A[i] <= 1000

First and only argument is an integer array A of length N.

Return an array of size four which contains indices of values P, Q, R, and S.

Input 1:

 A = [3, 4, 7, 1, 2, 9, 8]

Input 2:

 A = [2, 5, 1, 6]

Output 1:

 [0, 2, 3, 5]

Output 2:

 [0, 1, 2, 3]

Explanation 1:

 A[0] + A[2] = A[3] + A[5]
 Note: indexes returned should be 0-based.

Explanation 2:

 A[0] + A[1] = A[2] + A[3]