class Solution {
public:
    vector<int> twoSum(vector<int>& numbers, int target) {
    int length=numbers.size();
    int left,right,cpl=length-1,m;
    int flag=0;
    vector<int> ans;
    for(int i=0;i<=length/2;++i)
    {
        left=i+1;
        right=cpl;
        while(left<=right)
        {
            m=(left+right)/2;
            if(numbers[i]+numbers[m]==target)
            {
                ans.emplace_back(i);
                ans.emplace_back(m);
                flag=1;
                break;
            }
            else if(numbers[i]+numbers[m]>target)
            {
                right=m-1;
            }
            else
            {
                left=m+1;
            }
        }
        if(flag)
            break;
    }
    return ans;
    }
};

双指针，左边遍历，右边二分。