Submission #483124

#	Time	Username	Problem	Language	Result	Execution time	Memory
483124		blue	Teleporters (IOI08_teleporters)	C++17	100 / 100	717 ms	33840 KiB

teleporters

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

const int mx = 2'100'000;

int* nxt;

int main()
{
    int N, M;
    cin >> N >> M;

    vector<int> ep(1+mx+1, 0);

    for(int i = 1; i <= N; i++)
    {
        int W, E;
        cin >> W >> E;
        ep[W] = +i;
        ep[E] = -i;
    }

    nxt = new int[mx + 100'000];
    nxt = nxt + mx/2 + 50'000;

    int lst = 0;
    for(int p = mx; p >= 0; p--)
    {
        if(ep[p] == 0) continue;
        // cerr << "x = " << p << ' ' << ep[p] << '\n';
        nxt[ep[p]] = lst;
        lst = ep[p];
    }

    nxt[0] = 0;

    // for(int i = 1; i <= N; i++) cerr << nxt[+i] << ' ' << nxt[-i] << '\n';

    vector<int> nw;
    bool* visit = new bool[mx + 100'000] + (mx/2 + 50'000);
    for(int i = 1; i <= N; i++) visit[i] = visit[-i] = 0;

    for(int p = 1; p <= mx; p++)
    {
        if(ep[p] == 0) continue;
        if(visit[-ep[p]]) continue;

        nw.push_back(0);
        for(int u = -ep[p]; u != 0 && !visit[u]; u = -nxt[u])
        {
            visit[u] = 1;
            nw[int(nw.size()-1)]++;
        }
    }

    reverse(nw.begin(), nw.end());
    int mn = nw.back();
    nw.pop_back();

    // cerr << "mn = " << mn << '\n';
    //
    // for(int f: nw) cerr << f << ' ';
    // cerr << '\n';

    int ans = mn;
    sort(nw.begin(), nw.end());
    int l = 0;
    while(1)
    {
        if(M <= 0) break;
        if(!nw.empty())
        {
            ans += nw.back();
            nw.pop_back();
            ans += 2;
        }
        else
        {
            ans += 2;
            l = !l;
        }

        M--;
    }

    if(l % 2 == 1)
        ans--;

    cout << ans << '\n';
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
• Subtask 9: 5 / 5
• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 5 / 5
• Subtask 13: 5 / 5
• Subtask 14: 5 / 5
• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
• Subtask 17: 5 / 5
• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 5 / 5