Wrong tc help

Debugging Help
#1

I was working on this problem:
http://www.usaco.org/index.php?page=viewproblem2&cpid=763

And this is my code

#include <iostream>
#include <map>
#include <set>
#include <unordered_set>
#include <vector>
using namespace std;
//method to caluclate the best cows
unordered_set<long long> getBestCows(map<long long,long long>& cows){
    unordered_set<long long> bestCows;
    map<long long,long long>::iterator it;
    long long maxValue=-2147483647;
    for(it = cows.begin();it!=cows.end();it++){
        maxValue=max(maxValue,it->second);
    }
    map<long long,long long>::iterator it2;

    for(it2 = cows.begin();it2!=cows.end();it2++){
       if(it2->second==maxValue){
           bestCows.insert(it2->first);
       }
    }
    return bestCows;

}
int main() {
//    freopen("measurement.in", "r", stdin);
//    freopen("measurement.out", "w", stdout);

    //read inputs
    long long N,G;
    cin>>N>>G;
    map<long long,pair<long long,long long>> days;
    unordered_set<long long> bestCows;
    map<long long,long long> cows;
    for(long long i=0;i<N;i++){
        long long input1,input2,input3;
        cin>>input1>>input2>>input3;
        days.insert({input1,{input2,input3}});
        cows.insert({input2,G});
        bestCows.insert(input2);
    }
    //input reading done
    long long ans=0;
    map<long long,pair<long long,long long>>::iterator it;
    long long curNumBest=-2147483647;
    for(it=days.begin();it!=days.end();it++){
        cows[it->second.first]+=it->second.second;
        
        //I know that this part is wrong but i dont know why. I need this because it makes it much more efficent
        if(cows[it->second.first]<curNumBest && bestCows.find(it->second.first)==bestCows.end()){
            continue;
        }
        //
        
        unordered_set<long long> cur=getBestCows(cows);
        //check if it changed
        if(cur!=bestCows){
            ans++;
            curNumBest=cows[*cur.begin()];
            bestCows=cur;
        }
    }
    cout<<ans;

    return 0;
}

I marked the part which I know is wrong in the comments. I don’t know why it is wrong though. When I remove it gives the right answer for all test cases, but it is slow. When I add it, it works on everything except for tc 6 and 9.

these are the results:

Screen Shot 2021-04-26 at 3.36.24 PM
Screen Shot 2021-04-26 at 3.36.24 PM1522×210 22 KB

Can someone tell me why that part is wrong?

#2

What do you mean by “it is slow”? Does it TLE?

#3

yeah, it TLE’s on 3 test cases

#4

I’d try optimizing your getBestCows function instead. It’s linear in complexity, so I’d recommend instead using a sorted map of milk production to cows instead of a sorted map of cows to milk production.

#5

You don’t have time to list the best cows, so you need to find a faster way to count when the list of best cows changes. What are all of the cases where it can change? There’s 3 or so, all which can be checked efficiently.