Submission #1080518

#	Time	Username	Problem	Language	Result	Execution time	Memory
1080518		aykhn	Longest Trip (IOI23_longesttrip)	C++17	85 / 100	13 ms	600 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>

using namespace std;

vector<int> longest_trip(int N, int D)
{
    vector<int> p1 = {0}, p2 = {1};
    for (int i = 2; i < N; i++)
    {
        if (are_connected({p1.back()}, {i})) p1.push_back(i);
        else if (are_connected({p2.back()}, {i})) p2.push_back(i);
        else 
        {
            while (!p2.empty()) 
            {
                p1.push_back(p2.back());
                p2.pop_back();
            }
            p2 = {i};
        }
    }
    if (p1.size() < p2.size()) swap(p1, p2);
    if (!are_connected(p1, p2)) return p1;
    if (are_connected({p1.back()}, {p2.back()}))
    {
        while (!p2.empty()) 
        {
            p1.push_back(p2.back());
            p2.pop_back();
        }
    }
    else if (are_connected({p1[0]}, {p2.back()}))
    {
        for (int &i : p1) p2.push_back(i);
        p1 = {};
        swap(p1, p2);
    }
    else if (are_connected({p1.back()}, {p2[0]}))
    {
        for (int &i : p2) p1.push_back(i);
        p2 = {};
    }
    else if (are_connected({p1[0]}, {p2[0]}))
    {
        reverse(p1.begin(), p1.end());
        for (int &i : p2) p1.push_back(i);
        p2 = {};
    }
    else
    {
        {
            int l = 0, r = (int)p1.size() - 1;
            while (l < r)
            {
                int mid = (l + r) >> 1;
                vector<int> q;
                for (int i = l; i <= mid; i++) q.push_back(p1[i]);
                if (are_connected(q, p2)) r = mid;
                else l = mid + 1;
            }
            vector<int> nw = {p1[l]};
            for (int i = (l + 1) % (int)p1.size(); i != l; i = (i + 1) % (int)p1.size())
            {
                nw.push_back(p1[i]);
            }
            swap(nw, p1);
        }
        {
            int l = 0, r = (int)p2.size() - 1;
            while (l < r)
            {
                int mid = (l + r) >> 1;
                vector<int> q;
                for (int i = l; i <= mid; i++) q.push_back(p2[i]);
                if (are_connected(q, {p1[0]})) r = mid;
                else l = mid + 1;
            }
            vector<int> nw = {p2[l]};
            for (int i = (l + 1) % (int)p2.size(); i != l; i = (i + 1) % (int)p2.size())
            {
                nw.push_back(p2[i]);
            }
            swap(nw, p2);
        }
        reverse(p1.begin(), p1.end());
        for (int &i : p2) p1.push_back(i);
        p2 = {};
    }
    return p1;
}

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 45 / 60