1. Two Sum

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 nums[0] + nums[1] = 2 + 7 = 9,

    return [0, 1].

class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        if (len(nums) < 2):
            return
        
        temp={}
        for i in range(len(nums)):
            x = nums[i]
            if target-x in temp:
                return (temp[target-x], i)
            temp[x] = i

以上