167. Two Sum II - Input Array Is Sorted

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) 
    {
        int n=nums.size();
        vector< pair<int, int>>p;
        for(int i=0; i<n; i++)
        {
            p.push_back(make_pair(nums[i],i+1));
        }
        sort(p.begin(), p.end());

        int i=0, j=n-1;
        while(i<j)
        {
            if((p[i].first + p[j].first)==target)
                return {p[i].second, p[j].second};
            else if((p[i].first + p[j].first)<target)
                  i++;
            else
                  j--;
        }
        return {}; 
    }
};