Submission #841268

#	Time	Username	Problem	Language	Result	Execution time	Memory
841268		I_love_Hoang_Yen	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	11 ms	296 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;

// Subtask 1: D == 3
vector<int> sub1(int n) {
    vector<int> res(n);
    std::iota(res.begin(), res.end(), 0);
    return res;
}

// Subtask 2: D == 2
vector<int> sub2(int n) {
    vector<int> res {0};
    for (int i = 1; i < n; i++) {
        if (are_connected({0}, {i})) {
            res.push_back(i);
            break;
        }
    }

    for (int i = 1; i < n; i++) {
        if (i == res[1]) continue;

        if (are_connected({res.back()}, {i})) {
            res.push_back(i);
        } else {
            res.insert(res.begin(), i);
        }
    }

    return res;
}

// Subtask 3: D == 1, return path with length >= Lmax / 2
vector<int> sub3(int n) {
    // maintain 2 paths
    vector<int> p1 {0}, p2 {1};

    for (int i = 2; i < n; ++i) {
        // consider p1.back(), p2.back(), i
        // -> there's at least 1 edge

        if (are_connected({p1.back()}, {i})) {
            p1.push_back(i);
        } else if (are_connected({p2.back()}, {i})) {
            p2.push_back(i);
        } else {
            reverse(p2.begin(), p2.end());
            p1.insert(p1.end(), p2.begin(), p2.end());
        }
    }
    if (p1.size() > p2.size()) return p1;
    return p2;
}

vector<int> longest_trip(int n, int d) {
    if (d == 3) return sub1(n);
    if (d == 2) return sub2(n);
    return sub3(n);
}

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