Two Sum

Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2. Please note that your returned answers (both index1 and index2) are not zero-based.

 注意事项

You may assume that each input would have exactly one solution.

您在真实的面试中是否遇到过这个题？ 

Yes

样例

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

return [1, 2]

解题思路：暴力剪枝，水过。。。。没有考虑负数情况，所以首先进行一次筛选，然后直接枚举出答案即可。

解题代码：

class Solution {public:    /*     * @param numbers : An array of Integer     * @param target : target = numbers[index1] + numbers[index2]     * @return : [index1+1, index2+1] (index1 < index2)     */    vector<int> twoSum(vector<int> &nums, int target) {        // write your code here        vector<int>tem;        map<int,int>tem1;        for(int i=0;i<nums.size();i++){            if(nums[i]<target){                tem.push_back(nums[i]);                tem1[nums[i]]=i;            }        }        vector<int> ans;        for(int i=0;i<tem.size();i++){            for(int j=i+1;j<tem.size();j++){                if(tem[i]+tem[j]==target){                    ans.push_back(tem1[tem[i]]+1);                    ans.push_back(tem1[tem[j]]+1);                    return ans;                }            }        }    }};