C++ binary search solution:

vector climbingLeaderboard(vector ranked, vector player) {

//erase the ranked duplicates
ranked.erase(unique(ranked.begin(), ranked.end()), ranked.end());

vector<int> result={};
for(int i=0; i<player.size(); i++){
    //for each player perform a binary search:
    int left=0,
    right=ranked.size()-1;
    int p = player.at(i);
    bool found = false;
    while(left<=right && !found){
        int mid = left + (right - left) / 2;
        if(ranked.at(mid) == p){
            result.push_back(mid+1);
            found = true;
        }          
        if(ranked.at(mid) > p){
            left = mid + 1;
        }
        else {
            right = mid - 1;
        }
    }
    if(!found){
        result.push_back(left+1);
        ranked.insert(ranked.begin()+left, p);
    }
}
return result;

}