Submission #1060259

#	Time	Username	Problem	Language	Result	Execution time	Memory
1060259		qilby	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	13 ms	644 KiB

longesttrip

#include <bits/stdc++.h>

#include "longesttrip.h"

using namespace std;

vector < int > longest_trip(int n, int d) {
    bool g = 0;
    vector < int > a = {0}, b = {1};

    for (int i = 2; i < n; i++) {
        if (g) {
            if (are_connected({a.back()}, {i})) a.push_back(i), g = 0;
            else b.push_back(i);
        } else {
            if (are_connected({a.back()}, {i})) a.push_back(i);
            else if (are_connected({b.back()}, {i})) b.push_back(i), g = 1;
            else {
                reverse(b.begin(), b.end());
                for (auto v : b) a.push_back(v);
                b = {i};
            }
        }
    }

    if (are_connected(a, b)) {
        if (are_connected({a.back()}, {b.back()})) {
            reverse(b.begin(), b.end());
            for (auto v : b) a.push_back(v);
            return a;
        } else if (are_connected({a.back()}, {b[0]})) {
            for (auto v : b) a.push_back(v);
            return a;
        } else if (are_connected({a[0]}, {b.back()})) {
            for (auto v : a) b.push_back(v);
            return b;
        } else if (are_connected({a[0]}, {b[0]})) {
            reverse(b.begin(), b.end());
            for (auto v : a) b.push_back(v);
            return b;
        } else {
            int l = 0, r = (int)a.size() - 1;

            while (l < r) {
                int mid = (l + r) >> 1;

                vector < int > crr;
                for (int i = 0; i <= mid; i++) crr.push_back(a[i]);

                if (are_connected(crr, b)) r = mid;
                else l = mid + 1;
            }

            int p = l;

            l = 0, r = (int)b.size() - 1;

            while (l < r) {
                int mid = (l + r) >> 1;

                vector < int > crr;
                for (int i = 0; i <= mid; i++) crr.push_back(b[i]);

                if (are_connected({a[p]}, crr)) r = mid;
                else l = mid + 1;
            }

            vector < int > res;

            for (int i = (p + 1) % (int)a.size(), s = 0; s < (int)a.size(); s++, i = (i + 1) % (int)a.size()) res.push_back(a[i]);
            for (int i = l, s = 0; s < (int)b.size(); s++, i = (i + 1) % (int)b.size()) res.push_back(b[i]);

            return res;
        }
    } else {
        return ((int)a.size() > (int)b.size() ? a : b);
    }

    return {};
}

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