two-sum

two-sum.py

def twoSum(self, nums: 'List[int]', target: 'int') -> 'List[int]':
    index = {}
    for i,num in enumerate(nums):
        # build dictionary
        if index.get(num) == None:
            index[num] = i;
        
        # if (target - num) is in dict
        if index.get(target - num) != None: 
            if i != index.get(target-num): # cannot use same element
                return [i, index.get(target - num)] # return position of two elements

36 ms solution for leetcode 1. Two Sum