equal.py

def equal(self, A):
        hash_map = {}
        n = len(A)
        res = []
        for i in range(n-1):
            for j in range(i+1,n):
                sum = A[i]+A[j]
                if sum in hash_map:
                    ab = hash_map[sum]
                    if ab[0]<i and ab[1] not in [i,j]:
                        res.append([ab[0],ab[1],i,j])
                else:
                    hash_map[sum]=[i,j]
        res.sort()
        return res[0]



"""
Given an array A of integers, find the index of values that satisfy A + B = C + D, where A,B,C & D are integers values in the array

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 int the array )  
S2 : A2 B2 C2 D2

S1 is lexicographically smaller than S2 iff
  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
Example:

Input: [3, 4, 7, 1, 2, 9, 8]
Output: [0, 2, 3, 5] (O index)


"""