Submission

Score: 0

User: mthai

Problemset: ห้องสมุดเมือง 3M

Language: cpp

Time: 0.002 second

Submitted On: 2026-03-04 21:46:14

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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;

    cin>>n;

    vector<pair<long long,long long>> book;
    vector<long long> freq;
    long long total=0;
    for(int i =0;i<n;i++){
        int a,b;
        cin>>a>>b;
        book.push_back({a,b});
        total+=b-a;

    }

    sort(book.begin(),book.end());

    for(int i =0;i<n;i++){
        int a=book[i].first;
        int b=book[i].second;
        freq.push_back(b-a);
    }
    
    long long mid;
    if(total==1){
        mid=(total-1)/2;
    }else{
        mid=(total/2)-1;
    }   
    long long prefix=0;
    long long reprefix;

    for(int i =0;i<n;i++){
        reprefix=prefix;
        prefix+=freq[i];
        if(mid<=prefix){
            int a = book[i].first;
            cout<<a+(mid-reprefix);
            return 0;
        }
        
    }
}