1 #Given an array of integers, return indices of the two numbers such that they add up to a specific target.
 2 #You may assume that each input would have exactly one solution, and you may not use the same element twice.
 3 #Example:
 4 #Given nums = [2, 7, 11, 15], target = 9,
 5 #Because nums[0] + nums[1] = 2 + 7 = 9,
 

 6 #return [0, 1].
 7 def twoSum(nums, target):
 8     dic = dict()
 9     for index,value in enumerate(nums):
10         sub = target - value
11         if sub in dic:
12             return [dic[sub],index]
13         else:
14             dic[value] = index
15 L=[1,2,3,5]
16 print(twoSum(L,7))

這道題的解題思路很簡單，利用python中的字典記錄記錄下每個元素出現的位置，也就是其他語言中的哈希表。

Leetcode 001-twosum