Getting error when I change variable data type from “int” to “long” in CPP program

Question

I am coded a solution for the problem: Kefka and Company which is on codeforces. problem link: https://codeforces.com/problemset/problem/580/B

I have made a vector of pairs. I use a for loop for traversing every pair of the vector. And I take in consideration the first element of the pair and run upper_bound function. Then I add all the 2nd elements in the pairs from the current index till the index provided by upper_bound. Then I compare the answer variable with current sum and update the answer variable.

code:

#include<bits/stdc++.h>
using namespace std;

int main(){
    long n,d,m,s;
    cin>>n>>d;
    vector< pair<long ,long> > v;
    for(long i=0;i<n;i++){
        cin>>m>>s;
        v.push_back( {m,s} );
    }
    sort(v.begin(),v.end());

    long ans=0;
    for(long i=0;i<n;i++){
        long j = upper_bound(v.begin(),v.end(), make_pair(v[i].first+d,INT_MIN) ) - v.begin();
        long x=0;
        long f=i;
        while(f<j){
            x+=v[f].second;
            f+=1;
        }
        ans=max(ans,x);
    }
    cout<<ans;
}

The code works fine and gives the correct result for smaller testcases but it cannot deal larger test cases. So i changed the 'int' datatype to 'long' but I get this error along with many other:

/usr/include/c++/6/bits/predefined_ops.h:72:22: error: no match for ‘operator<’ (operand types are ‘const std::pair’ and ‘std::pair’)

       { return __val < *__it; }


 

Answer 1

Comparing std::pair s is only supported if the template arguments are the same.

In your code, make_pair(v[i].first+d,INT_MIN) produce the type std::pair<long,int> .

You likely meant make_pair(v[i].first+d,LONG_MIN)

(See it compile successfully)