167. Two Sum II

题目来源【Leetcode】

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.

You may assume that each input would have exactly one solution and you may not use the same element twice.

Input: numbers={2, 7, 11, 15}, target=9
Output: index1=1, index2=2

这道题前后相加比较，如果大了则h-1，小了则l+1，直到相等

class Solution {public:    vector<int> twoSum(vector<int>& numbers, int target) {        int l = 0;        int h = numbers.size()-1;        while(l <= h){            if(numbers[l] + numbers[h] < target)  l++;            else if(numbers[l] + numbers[h] > target) h--;            else break;        }        vector<int>pair;        pair.push_back(l+1);        pair.push_back(h+1);        return pair;    }};