Submission #846737

#	Time	Username	Problem	Language	Result	Execution time	Memory
846737		IvanJ	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	6 ms	600 KiB

longesttrip

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

#define pb push_back
#define all(a) (a).begin(), (a).end()

using namespace std;

vector<int> longest_trip(int n, int D) {
    if(D == 3) {
        vector<int> p;
        for(int i = 0;i < n;i++) p.pb(i);
        return p;
    }
    if(D == 2) {
        deque<int> dq;
        if(!are_connected({0}, {1}))
            dq.pb(0), dq.pb(2), dq.pb(1);
        else if(!are_connected({1}, {2}))
            dq.pb(1), dq.pb(0), dq.pb(2);
        else dq.pb(0), dq.pb(1), dq.pb(2);

        for(int i = 3;i < n;i++) {
            if(are_connected({i}, {dq.front()}))
                dq.push_front(i);
            else dq.pb(i);
        }

        return vector<int>(all(dq));
    }
    if(D == 1) {
        vector<int> p1, p2;
        if(n & 1) p1.pb(n - 1);
        for(int i = 1;i < n;i += 2) {
            int a = i - 1, b = i;

            if(p2.size()) {
                int c = p1.back(), d = p2.back();
                if(are_connected({a}, {b})) {
                    if(are_connected({a}, {c})) {
                        p1.pb(a), p1.pb(b);
                        if(are_connected({b}, {d})) {
                            while(p2.size()) 
                                p1.pb(p2.back()), p2.pop_back();
                        }
                    }  else {
                        p2.pb(a), p2.pb(b);
                        if(are_connected({b}, {c})) {
                            while(p1.size()) 
                                p2.pb(p1.size()), p1.pop_back();
                        }
                    }
                } else {
                    if(are_connected({a}, {c})) {
                        if(are_connected({b}, {d})) 
                            p1.pb(a), p2.pb(b);
                        else p1.pb(b), p2.pb(a);
                    } else p1.pb(b), p2.pb(a);
                }
            } else {
                if(are_connected({a}, {b})) {
                    if(p1.size() == 0)
                        p1.pb(a), p1.pb(b);
                    else if(are_connected({a}, {p1.back()})) {
                        p1.pb(a), p1.pb(b);
                    } else {
                        if(are_connected({b}, {p1.back()})) 
                            p1.pb(b), p1.pb(a);
                        else p2.pb(a), p2.pb(b);
                    }
                } else {
                    if(p1.size() == 0)
                        p1.pb(a), p2.pb(b);
                    else if(are_connected({a}, {p1.back()}))
                        p1.pb(a), p2.pb(b);
                    else p1.pb(b), p2.pb(a);
                }

            }

            if(p1.size() < p2.size()) swap(p1, p2);
        }
        assert(0 != 0);
        for(int i = 1;i < (int)p1.size();i++) 
            assert(are_connected({p1[i - 1]}, {p1[i]}));
        return p1;
    }
    return {};
}

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