Submission #1281429

#	Time	Username	Problem	Language	Result	Execution time	Memory
1281429		red_souls	Fire (BOI24_fire)	C++17	0 / 100	1 ms	580 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define task "FIRE"
using namespace std;

const int N = 1e6 + 16;
const ll INF = 1e18;
int n, m;
ll s[N], e[N];

namespace sub6 {
    ll cnt, result = INF;
    pair <ll, ll> a[N];

    vector < pair <ll, ll> > checkLines;
    ll maxx;

    void compress() {
        vector <ll> c;
        for (int i = 1; i <= n; i++) {
            c.push_back(a[i].first);
            c.push_back(a[i].second);
        }
        for (auto x : checkLines) {
            c.push_back(x.first);
            c.push_back(x.second);
        }
        sort(c.begin(), c.end());
        c.erase(unique(c.begin(), c.end()), c.end());
        for (int i = 1; i <= n; i++) {
            a[i].first = lower_bound(c.begin(), c.end(), a[i].first) - c.begin() + 1;
            a[i].second = lower_bound(c.begin(), c.end(), a[i].second) - c.begin() + 1;
            maxx = max(maxx, a[i].first);
            maxx = max(maxx, a[i].second);
        }
        for (auto &x : checkLines) {
            x.first = lower_bound(c.begin(), c.end(), x.first) - c.begin() + 1;
            x.second = lower_bound(c.begin(), c.end(), x.second) - c.begin() + 1;
            maxx = max(maxx, x.first);
            maxx = max(maxx, x.second);
        }
    }

    ll maxR[N], up[N][26];

    void solve() {
        checkLines.push_back({0, m - 1});
        for (int i = 1; i <= n; i++) {
            if (s[i] > e[i]) {
                checkLines.push_back({e[i], e[i] + m - 1});
                e[i] += m;
            }
            a[i] = {s[i], e[i] - 1};
        }
        compress();

        for (int i = 1; i <= n; i++) {
            maxR[a[i].first] = a[i].second;
        }
        for (int i = 1; i <= maxx; i++) {
            maxR[i] = max(maxR[i - 1], maxR[i]);
        }
        for (int i = maxx; i >= 1; i--) {
            if (maxR[i] != maxR[i + 1]) {
                up[i][0] = i;
            }
            else {
                up[i][0] = up[i + 1][0];
            }
        }
        for (auto x : checkLines) {
            bool flag = true;
            for (int i = x.first; i <= x.second; i++) {
                if (maxR[i] == 0) {
                    flag = false;
                    break;
                }
            }
            if (!flag) {
                continue;
            }
            int u = x.first, v = x.second, ans = 0;
            while (u <= v) {
                int k = -1;
                for (int i = 20; i >= 0; i--) {
                    if (up[u][i] == 0) {
                        continue;
                    }
                    if (up[u][i] < v) {
                        k = i;
                        break;
                    }
                }
                if (k == -1) {
                    break;
                }
                u = up[u][k] + 1;
                ans += (1 << k);
            }
            ans++;
            result = min(result, 1LL * ans);
        }
        if (result > n) {
            result = -1;
        }
        cout << result;
    }
}

int main() {
    ios_base :: sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> s[i] >> e[i];
    }
    sub6 :: solve();

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:116:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:117:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  117 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 17
• Subtask 3: 0 / 9
• Subtask 4: 0 / 13
• Subtask 5: 0 / 21
• Subtask 6: 0 / 26