given an array of integers return indices of the two numbers such that they add up to a specific target you may assume that each input would have exactly one solution and you may not use the same element twice example given nums 2 7 11 15 target 9 because nums0 nums1 2 7 9 return 0 1
def two_sum(array, target):
    dic = {}
    for i, num in enumerate(array):
        if num in dic:
            return dic[num], i
        else:
            dic[target - num] = i
    return None