Tareq Intervals #2

#include <bits/stdc++.h>
#define F first
#define S second
//#define mp make_pair
#define pb push_back

using namespace std;
typedef long long ll;

const int MOD = 1e9 + 7;
const int N = 2e5 + 9;
const int INF = 1e9 + 5;

vector <pair <int, int> > events;

bool cmp (pair <int, int> p1, pair <int, int> p2) {
    if (p1.F == p2.F)
        return p1.S > p2.S;
    return p1.F <= p2.F;
}

void solve () {
    int n, k;
    cin >> n >> k;

    for (int i = 1; i <= n; i++) {
        int l, r;
        cin >> l >> r;

        if (l + k - 1 > r)
            continue;

        events.pb ({l, +1});
        events.pb ({r - k + 1, -1});
    }

    int res = 0, currentlyOpened = 0;
    sort (events.begin(), events.end(), cmp);

    for (auto e: events) {
        currentlyOpened += e.S;
        res = max (res, currentlyOpened);
    }

    cout << res << "\n";

    return;
}

int main () {
    int t = 1;
    //cin >> t;

    while (t--)
        solve ();

    return 0;
}