Submission #1303563

#	Time	Username	Problem	Language	Result	Execution time	Memory
1303563		wedonttalkanymore	Fire (BOI24_fire)	C++20	100 / 100	320 ms	100596 KiB

Main

#include <bits/stdc++.h>
/*
    Checklist: 
    - Check statement: 
    - Check filename: 
    - Check test limit: 
    - Stresstest: 
*/
using namespace std;
using ll = long long;

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 5e5 + 5, inf = 1e18, mod = 1e9 + 7, block = 320, lim = 19;

int n, m;
pii a[N];

struct ST {
    vector <pii> st;
    ST (int _n) {
        st.assign(4 * (_n + 5), make_pair(0, 0));
    }
    void build(int i, int l, int r) {
        if (l == r) {
            st[i] = make_pair(a[l].se, l);
            return;
        }
        int mid = (l + r) / 2;
        build(2 * i, l, mid);
        build(2 * i + 1, mid + 1, r);
        st[i] = st[2 * i];
        if (st[i].fi < st[2 * i + 1].fi) {
            st[i] = st[2 * i + 1];
        }
        else if (st[i].fi == st[2 * i + 1].fi) {
            st[i].se = max(st[i].se, st[2 * i + 1].se);
        }
    }
    pii get(int i, int l, int r, int u, int v) {
        if (u > r || v < l) return make_pair(0, 0);
        if (u <= l && r <= v) return st[i];
        int mid = (l + r) / 2;
        pii L = get(2 * i, l, mid, u, v);
        pii R = get(2 * i + 1, mid + 1, r, u, v);
        pii res = L;
        if (res.fi < R.fi) {
            res = R;
        }
        else if (res.fi == R.fi) {
            res.se = max(res.se, R.se);
        }
        return res;
    }
} St(N);

int up[N][lim + 1];

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }
    cin >> n >> m;
    int sz = n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i].fi >> a[i].se;
        if (a[i].fi < a[i].se) {
            a[++sz] = make_pair(a[i].fi + m, a[i].se + m);
        }
        else {
            a[i].se += m;
        }
    }
    sort(a + 1, a + sz + 1);
    St.build(1, 1, sz);
    for (int i = 1; i <= sz; i++) {
        int L = lower_bound(a + 1, a + sz + 1, make_pair(a[i].fi, -inf)) - a;
        int R = upper_bound(a + 1, a + sz + 1, make_pair(a[i].se, inf)) - a - 1;
        pii val = St.get(1, 1, sz, L, R);
        if (val.fi > a[i].se) up[i][0] = val.se;
        // cout << i << ' ' << val.se << ' ' << val.fi << '\n';
    }
    for (int i = 1; i <= lim; i++) {
        for (int j = 1; j <= sz; j++) {
            up[j][i] = up[up[j][i - 1]][i - 1];
        }
    }
    int ans = inf;
    for (int i = 1; i <= sz; i++) {
        if (a[i].fi >= m) break;
        int tg = a[i].fi + m;
        if (a[i].se >= tg) {
            ans = min(ans, 1ll);
            continue;
        }
        int cur = i, cnt = 1;
        for (int k = lim; k >= 0; k--) {
            int nxt = up[cur][k];
            if (nxt != 0 && a[nxt].se < tg) {
                cur = nxt;
                cnt += (1ll << k);
            }
        }
        int nxt = up[cur][0];
        if (nxt != 0 && a[nxt].se >= tg) {
            cnt++;
            ans = min(ans, cnt);
        }
    }
    cout << (ans < inf ? ans : -1);
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:66:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
Main.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 13 / 13
• Subtask 5: 21 / 21
• Subtask 6: 26 / 26