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].
思路：
用dictionary 存期望得到的数{期望数:期望数的index}（期望数= 目标数-当前数）
循环list 判断期望值是否在 dict 如果存在 则 返回对应的key 否则存期望数，接着找
"""
def twoSum(nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
dict_num = {}
for key, value in enumerate(nums):
depand = target - value
if dict_num.__contains__(depand):
return dict_num.get(depand), key
dict_num[value] = key
if __name__ == '__main__':
print(twoSum([2, 7, 11, 15], 9))
