leetcode-Two Sum II - Input array is sorted-167

输入一个递增序列，求两个元素的和等于target的下标

数组求和系列问题，用头尾指针法，ON

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