[LeetCode] 1. Two Sum_Easy

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]
         """
          d =  {}
         for index, num in enumerate(nums):
             if target -num in d:
                 return [d[target-num], index]
             d[num] = index
         #return []      # 可以不要, 因为题目说肯定有一个solution