Link to this code:
https://cses.fi/paste/6a4ab6fb947c1fe7f5369//// BISMILLAHIR RAHMANIR RAHEEM
/// ALLAH IS WATCHING ME
/// ALLAH save us from COVID-19.Amin.
/// Every soul shall taste death.
/// Tag ::
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
/// order_of_key return number of elements less than x.
/// find_by_order return index.
using namespace std;
using namespace __gnu_pbds;
#define MOHAMMAD ios::sync_with_stdio(0);cin.tie(0);
#define all(x) (x).begin(), (x).end()
#define AE cout << fixed << setprecision(2);
/// faster.
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
int dx8[] = {0, 0, 1, 1, 1, -1, -1, -1}; // 8-direction.......
int dy8[] = {1,-1, 1, -1, 0, 0, -1, 1};
int dx4[]= {1,-1,0,0}; // 4-direction...........
int dy4[]= {0,0,1,-1};
using ll = long long;
const ll MOD = 1e9 + 7;
typedef tree< int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
typedef tree<pair<int, int>,null_type,less<pair<int, int>>,rb_tree_tag,tree_order_statistics_node_update> ordered_multiset;
//debug
template<typename F,typename S>ostream&operator<<(ostream&os,const pair<F,S>&p){return os<<"("<<p.first<<", "<<p.second<<")";}
template<typename T>ostream&operator<<(ostream&os,const vector<T>&v){os<<"{";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())os<<", ";os<<*it;}return os<<"}";}
template<typename T>ostream&operator<<(ostream&os,const set<T>&v){os<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())os<<",";os<<*it;}return os<<"]";}
template<typename T>ostream&operator<<(ostream&os,const multiset<T>&v) {os<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())os<<", ";os<<*it;}return os<<"]";}
template<typename F,typename S>ostream&operator<<(ostream&os,const map<F,S>&v){os<<"[";for(auto it=v.begin();it!=v.end();++it){if(it!=v.begin())os<<", ";os<<it->first<<" = "<<it->second;}return os<<"]";}
#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0)
void faltu(){cerr << endl;}
template<typename T>void faltu(T a[],int n){for(int i=0;i<n;++i)cerr<<a[i]<<' ';cerr<<endl;}
template<typename T,typename...hello>void faltu(T arg,const hello&...rest){cerr<<arg<<' ';faltu(rest...);}
//#else
//#define dbg(args...)
/// Modular arithmetic
inline void normal(ll &a) { a %= MOD; (a < 0) && (a += MOD); }
inline ll modMul(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); return (a*b)%MOD; }
inline ll modAdd(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); return (a+b)%MOD; }
inline ll modSub(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); a -= b; normal(a); return a; }
inline ll modPow(ll b, ll p) { ll r = 1; while(p) { if(p&1) r = modMul(r, b); b = modMul(b, b); p >>= 1; } return r; }
inline ll modInverse(ll a) { return modPow(a, MOD-2); } /// When MOD is prime.
inline ll modDiv(ll a, ll b) { return modMul(a, modInverse(b)); }
//*********************************************** The END **********************************************************************************************************************************
const ll N = 1e5;
const ll INF = 1e18;
const ll limit = (1LL<<64) - 1;
int main()
{
MOHAMMAD
ll n , a , b;
cin >> n;
vector < pair < ll , ll > > v;
for ( ll i = 0 ; i<n ; i++ ){
cin >> a >> b;
v.push_back ( { a , 1 } );
v.push_back ( { b , -1 } );
}
sort ( all ( v ) );
ll mx = 0 , cur = 0;
for ( auto it : v ){
cur+=it.second;
mx = max ( cur , mx );
}
cout << mx;
}
/*
Explanation:
1
8
1 1 2 2 2 2 4 4
----------------------------------------------------------------------------------------------------------------
Topic :: Bellman-Ford Algorithm
Practice ::
1. https://open.kattis.com/problems/allpairspath
2. https://www.spoj.com/problems/SEGMENTS/
3. https://cses.fi/problemset/task/1673
4. https://cses.fi/problemset/task/1197
5.
Alhamdulillah
*/