Submission #1066670

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066670		vjudge1	Fire (BOI24_fire)	C++17	0 / 100	2069 ms	10700 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using i64 = long long;

constexpr int mxN = 200'000;
int N, M;
pair<int,int> se[mxN + 1];
vector<int> normal;
i64 dp[3 * mxN + 5];

int getNorm(int x) {
    int lo = 0, hi = (int) normal.size() - 1;
    while (lo <= hi) {
        int mid = lo + (hi - lo) / 2;
        if (normal[mid] == x) return mid;
        else if (normal[mid] < x) lo = mid + 1;
        else hi = mid - 1;
    }
    return -1;
}

void solve() {
    cin >> N >> M;
    for (int i = 0; i < N; i++) {
        cin >> se[i].first >> se[i].second;
        if (se[i].second < se[i].first) {
            se[i].second += M;
            normal.emplace_back(se[i].second - M);
        }
        normal.emplace_back(se[i].first);
        normal.emplace_back(se[i].second);
    }

    sort(normal.begin(), normal.end());
    normal.erase(unique(normal.begin(), normal.end()), normal.end());

    for (int i = 0; i < N; i++) {
        se[i].first = getNorm(se[i].first);
        se[i].second = getNorm(se[i].second);
    }
    sort(se, se + N, [](const auto x, const auto y){
        return x.second < y.second;
    });

    i64 ans = 1LL * (N + 1) * (N + 1);

    for (int i = 0; i < (int) normal.size(); i++) {
        dp[i] = 1LL * i * (N + 1);
    }

    int id = 0;
    for (int i = 0; i < (int) normal.size(); i++) {
        for (; id < N && se[id].second == i; id++) {
            int l = se[id].first;
            for (int j = l; j <= i; j++) {
                dp[j] = min(dp[j], dp[l] + 1);
            }
            if (normal[i] >= M) {
                ans = min(ans, 1 + dp[l] - dp[getNorm(i - M)]);
            }
        }
    }

    if (ans > N) ans = -1;
    cout << ans << '\n';
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int tc = 1; 
    //cin >> tc;
    while (tc--) {
        solve();
    }

    return 0;
}

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