Submission #721655

#	Time	Username	Problem	Language	Result	Execution time	Memory
721655		MDSPro	Event Hopping (BOI22_events)	C++14	0 / 100	63 ms	11668 KiB

events

#include "bits/stdc++.h"

using namespace std;

int main(){
    cin.tie(0)->sync_with_stdio(0);

    int n,q; cin >> n >> q;
    vector<tuple<int,int,int>> ev;
    for(int i = 0; i < n; ++i){
        int x,y; cin >> x >> y;
        ev.emplace_back(x,y,i+1);
    }

    sort(ev.begin(),ev.end());  

    vector<int> nw_order(n+1);
    vector<int> left(n+1),right(n+1);
    for(int i = 0; i < n; ++i) {
        left[i] = get<0>(ev[i]);
        right[i] = get<1>(ev[i]);
        nw_order[get<2>(ev[i])] = i;
    }

    vector<vector<int>> nxt(20,vector<int>(n+1));
    nxt[0][n-1] = nxt[0][n] = n;

    int r = 0;
    for(int i = 0; i < n-1; ++i){
        while(r+1 < n && left[r+1] <= right[i]) r++;
        nxt[0][i] = r;
    }
    
    for(int i = 1; i < 20; ++i) {
        for(int j = 0; j <= n; ++j){
            nxt[i][j] = nxt[i-1][nxt[i-1][j]];
        }
    }

    auto get = [&](int x, int y){
        int cur = 0;
        for(int i = 19; i >= 0; --i){
            if(nxt[i][x] <= y) {
                cur |= (i<<1);
                x = nxt[i][x];
            }
        }

        return cur;
    };

    while(q--){
        int a,b; cin >> a >> b;
        a = nw_order[a];
        b = nw_order[b];

        if(a == b) cout << "0\n";
        else if(a > b) cout << "impossible\n";
        else cout << get(a,b) << '\n';
    }
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30