(LeetCode)Two Sum --- 求和指定的索引

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.

Example:

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

UPDATE (2016/2/13):

The return format had been changed to zero-based indices. Please read the above updated description carefully.

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解题分析：

此题目由于是在2月13日有更新，此处需要注意。目前的索引是从0开始的。

思路可以利用key-value模式的方法，key为索引，value为值，这样就可以

利用A : Aindex + B:Bindex = target公式来求出所求索引。

# -*- coding:utf-8 -*-
__author__ = 'jiuzhang'
class Solution(object):
    def twoSum(self, nums, target):
        dict = {}
        for index in xrange(len(nums)):
            if target - nums[index] in dict:
                return [dict[target - nums[index]], index]
            dict[nums[index]] = index