示例：
nums = [1,2,5,7] target = [6]
return [0,2]
解决方案1：
for i in range(len(nums)): remain = target - nums[i] if remain in nums and nums.index(remain) != i: return [i,nums.index(remain)]
解决方案2（转载于leetcode用户Dirk41）：
data = { nums[i]: i for i,n in enumerate(nums)}
for i in range(len(nums)):
complement = target - nums[i]
if complement in data and data.get(complement) != i:
return [i, data.get(complement)]
方案2的运行速度快很多倍
Two sum（给定一个无重复数组和目标值，查找数组中和为目标值的两个数，并输出其下标）
原文：https://www.cnblogs.com/wenqinchao/p/10523148.html