SIT-Prac-I

#include <bits/stdc++.h>

#pragma GCC optimize("O3")
#pragma GCC target("avx")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ll long long
#define MP make_pair
#define ERR cout << "================================================\n"
#define fi first
#define se second
#define PB push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define forn(i, n) for (ll i = 0; i < (ll)(n); ++i)
#define for1(i, n) for (ll i = 1; i <= (ll)(n); ++i)
#define ford(i, n) for (ll i = (ll)(n)-1; i >= 0; --i)
#define fore(i, a, b) for (ll i = (ll)(a); i <= (ll)(b); ++i)
#define print(v)          \
    for (auto x : v)      \
    {                     \
        cout << x << " "; \
    }
#define umin(...) min({__VA_ARGS__})
#define umax(...) max({__VA_ARGS__})
#define MAX(v) *max_element(all(v))
#define MIN(v) *min_element(all(v))
#define SP << " " <<
#define W(t)  \
    ll t;     \
    cin >> t; \
    while (t--)
#define FIO                           \
    freopen("input.txt", "r", stdin); \
    freopen("output.txt", "w", stdout);
#define FAST                 \
    ios::sync_with_stdio(0); \
    cin.tie(0);              \
    cout.tie(0);

using namespace std;

typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef vector<vll> vvll;

const ll INF = 1e18;
const ll NEG_INF = -1 * (1e18);
using namespace std;

void usaco(string prob)
{
    freopen((prob + ".in").c_str(), "r", stdin);
    freopen((prob + ".out").c_str(), "w", stdout);
}

/* Function to check primality in O(sqrt(n)) */
bool prime(int n)
{
    if (n < 2)
        return false;
    for (int x = 2; x * x <= n; x++)
    {
        if (n % x == 0)
            return false;
    }
    return true;
}

/* Function to get prime factorization of n */
vector<int> getFactors(int n)
{
    vector<int> f;
    for (int x = 2; x * x <= n; x++)
    {
        while (n % x == 0)
        {
            f.push_back(x);
            n /= x;
        }
    }
    if (n > 1)
        f.push_back(n);
    return f;
}

void solve()
{
    ll n, m, ans = 0;
    ;
    cin >> n >> m;
    vector<pair<ll, ll>> v(n);
    forn(i, n)
    {
        cin >> v[i].fi >> v[i].se;
        v[i].se += v[i].fi;
    }

    sort(all(v));
    vll a;
    forn(i, n)
    {
        a.PB(v[i].fi);
        a.PB(v[i].se);
    }
    sort(all(a));
    v.PB({1e7 + 5, 1e7 + 5}); // may be unnecessary ??
    forn(i, 2 * n)
    {
        ll temp_ans = 0;
        ll start = a[i], end = a[i] + m;
        forn(j, n)
        {
            if (v[j].fi <= a[i] && a[i] <= v[j].se)
            {
                v[j].fi = a[i];
            }
        }

        forn(j, n)
        {
            if (start <= v[j].fi && v[j].fi <= end)
            {
                temp_ans++;
            }
        }
        ans = max(ans, temp_ans);
    }
    cout << ans << "\n";
}

int main()
{
    //FIO
    FAST

        //usaco("cowlands");

        ll TC = 1;
    /*
    Uncomment when multiple test cases
    */

    //cin >> TC;
    for1(tt, TC)
    {
        solve();
    }
    return 0;
}

/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?)
    * do smth instead of nothing and stay organized
    * WRITE STUFF DOWN
*/