Submission

Score: 0

User: Kitsunox

Problemset: ห้องสมุดเมือง 3M

Language: cpp

Time: 0.000 second

Submitted On: 2025-12-14 00:16:13

#include <bits/stdc++.h>
using namespace std;
#define int long long
int n,cont;
vector<pair<int,int>> mp;

int32_t ch(int md){
    int x = 0;
    for(auto [a,b] : mp){
        if(md >= a+b-1){
            x += b;
        }else if(md >= a){
            x += md - a + 1;
        }
    }
    return x;
}

int main(){
    cin >> n;
    for(int i = 0;i < n;i++){
        int a,b;
        cin >> a >> b;
        mp.push_back({a,b});
        cont += b-a;
    }
    int l = 0, r = 2e7+5,mdi = cont / 2;
    while(l < r){
        int md = (l+r)/2;
        if(ch(md) >= mdi) r = md;
        else l = md+1;
    }
    cout << l;
}