Submission #1080415

#	Time	Username	Problem	Language	Result	Execution time	Memory
1080415		someone	Fire (BOI24_fire)	C++14	100 / 100	294 ms	48108 KiB

Main

#include <bits/stdc++.h>
#define sz(x) ((int)x.size())
#define all(x) x.begin(), x.end()
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
using namespace std;

const int N = 4e5 + 42, T = 18, INF = 1e9 + 42;

struct Inter {
    int l, r;
};

struct Event {
    int t, id, isDeb;
};

int bl[T][N];

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n, m; cin >> n >> m;
    
    vector<Inter> inter;
    for(int i = 0; i < n; i++) {
        int s, e; cin >> s >> e;
        if(s < e) {
            inter.push_back({s, e});
            inter.push_back({s+m, e+m});
        } else {
            inter.push_back({s, e+m});
        }
    }
    vector<Event> ev;
    for(int i = 0; i < sz(inter); i++) {
        ev.push_back({inter[i].l, i, 0});
        ev.push_back({inter[i].r, i, 1});
    }
    sort(all(ev),
    [](Event a, Event b) {
        if(a.t == b.t) return a.isDeb < b.isDeb;
        return a.t < b.t;
    });

    set<array<int, 2>> fins;
    vector<bool> occ(sz(inter));
    for(Event e : ev) {
        if(occ[e.id]) {
            occ[e.id] = 0;
            auto it = fins.end();
            it--;
            bl[0][e.id] = (*it)[1];
            fins.erase(array<int, 2>{inter[e.id].r, e.id});
        } else {
            occ[e.id] = 1;
            fins.insert(array<int, 2>{inter[e.id].r, e.id});
        }
    }
    for(int i = 1; i < T; i++)
        for(int j = 0; j < sz(inter); j++)
            bl[i][j] = bl[i-1][bl[i-1][j]];
    
    int mini = INF;
    for(int i = 0; i < sz(inter); i++) if(inter[i].l <= m) {
        int id = i, ans = 2;
        for(int j = T-1; j >= 0; j--)
            if((j == 0 || bl[j][id] != bl[j-1][id]) && inter[bl[j][id]].r < inter[i].l + m) {
                ans += (1 << j);
                id = bl[j][id];
            }
        if(inter[bl[0][id]].r >= inter[i].l + m)
            mini = min(mini, ans);
    }

    cout << (mini == INF ? -1 : mini) << '\n';
}

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