Submission

Score: 0

User: sulinx

Problemset: ห้องสมุดเมือง 3M

Language: cpp

Time: 0.002 second

Submitted On: 2026-02-14 17:01:21

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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;

    vector<pair<int,int>> range;
    int rmax = 0;
    int rmin = INT_MAX;
    ll total = 0;
    
    for(int i = 0;i<n;i++){
        int x,y;
        cin >> x >> y;

        rmax = max(rmax,y);
        rmin = min(rmin,y);
        range.push_back({x,y});

        total += y-x;
    }
    
    int tmp = total/2; 
    int left = rmin,right = rmax,med = 0;

    while(left<= right){
        int mid = left + (right - left)/2;

        int p2mid = 0;
        for(auto&r:range){
            int start = r.first;
            int end = r.second;
            int count = min(end,mid+1) - start;
            if(count > 0){
                p2mid += count;
            }
        }

        if(p2mid>=tmp){
            med = mid;
            right = mid-1;
        }else{
            left = mid+1;
        }
    }
    cout << med << '\n';
    return 0;
}