Given an array of integers, return indices of the two numbers such that they add up to a specific target.

The below python code will return the first solution found, and assumes that no element appears twice.

def twoSum(nums, target): """ :type nums: List[int] :type target: int :rtype: List[int] """ index_map = {} for i in range(len(nums)): num = nums[i] pair = target - num if pair in index_map: return [index_map[pair], i] index_map[num] = i return None nums = [1,4,8,3,2,9,15] target = 13 print("Nums: ", nums) print("Target: ", target) print("Solution: ", twoSum(nums, target)) print() nums = [2,7,11,15] target = 9 print("Nums: ", nums) print("Target: ", target) print("Solution: ", twoSum(nums, target))

Output:

Nums: [1, 4, 8, 3, 2, 9, 15] Target: 13 Solution: [1, 5] Nums: [2, 7, 11, 15] Target: 9 Solution: [0, 1]

Hope it helps.