Two Sum II - Input array is sorted -E

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.

Note:

• 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.

Example:

Input: numbers = [2,7,11,15], target = 9
Output: [1,2]
Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.

A:
就是简单的two Pointer 方法

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