Restaurant Customers

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

int main() {
    int n;
    cin >> n;

    vector<pair<int, int>> v;
    for(int i = 0; i < n; ++i) {
        int a, b;
        cin >> a >> b;
        v.push_back({a, b});
    }

    set<int> S;
    for(auto [a, b] : v) {
        S.insert(a);
        S.insert(b);
    }

    map<int, int> mapTo;
    int nextNum = 1;

    for(int num : S)
        mapTo[num] = nextNum++;

    for(int i = 0; i < n; ++i) {
        v[i].first = mapTo[ v[i].first ];
        v[i].second = mapTo[ v[i].second ];
    }

    // ------- solução em baixo

    vector<int> cnt(500000);

    for(int i = 0; i < n; ++i) {
        cnt[ v[i].first ]++;
        cnt[ v[i].second + 1 ]--;
    }

    int ans = 0;
    for(int i = 1; i < cnt.size(); ++i) {
        cnt[i] += cnt[i - 1];
        ans = max(ans, cnt[i]);
    }

    cout << ans << '\n';

    return 0;
}