2576. Find the Maximum Number of Marked Indices

class Solution {
public:
    int maxNumOfMarkedIndices(vector<int>&v) {
        sort(v.begin(),v.end());
        int i=0,n=v.size(),j=n/2,cnt=0;
        while(i<n/2 && j<n){
            if(v[i]*2<=v[j]){
                i++;
                j++;
                cnt+=2;
            }
            else j++;
        }
        return cnt;
    }
};