Submission #1030210

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030210		Agreb	Longest Trip (IOI23_longesttrip)	C++17	60 / 100	864 ms	852 KiB

longesttrip

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

vector <int> longest_trip(int N, int D){
    vector <vector<int>> gr(N, vector<int>(N, 0));
    vector <int> path;
    for (int i = 0; i < N; i++){
        for (int j = 0; j < i; j++){
            vector <int> a{i}, b{j};
            int f = are_connected(a, b);
            gr[i][j] = gr[j][i] = f;
            if (gr[i][j]){
                path = {i, j};
            }
        }
    }
    
    if (N == 1){
        return vector<int>{0};
    }
    if (N == 2){
        if (gr[0][1]) return vector<int>{0, 1};
        else return vector <int>{0};
    }
    assert(!path.empty());
    
    vector <int> on_path(N);
    for (int u : path) on_path[u] = 1;

    while (path.size() < N){
        int P = path.size();
        int st = path[0], fin = path[P-1];

        int done = 0;
        for (int v = 0; v < N; v++){
            if (!on_path[v]){
                if (gr[st][v]){
                    reverse(path.begin(), path.end());
                    path.push_back(v);
                    on_path[v] = 1;
                    done = 1;
                    break;
                }
                if (gr[fin][v]){
                    path.push_back(v);
                    on_path[v] = 1;
                    done = 1;
                    break;
                }
            }
        }
        if (done) continue;

        assert(gr[st][fin] == 1);
        for (int v = 0; v < N; v++){
            if (!on_path[v]){
                for (int i = 0; i < P; i++){
                    if (gr[path[i]][v]){
                        vector <int> npath;
                        for (int j = 0; j < P; j++) 
                            npath.push_back(path[(j+i+1)%P]);
                        npath.push_back(v);
                        path = npath;
                        on_path[v] = 1;
                        done = 1;
                        break;
                    }
                }
                if (done) break;
            }
        }
        if (done) continue;

        if (P >= N - P) return path;
        else{
            vector <int> npath;
            for (int v = 0; v < N; v++){
                if (!on_path[v]) npath.push_back(v);
            }
            return npath;
        }
    }
    return path;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:31:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   31 |     while (path.size() < N){
      |            ~~~~~~~~~~~~^~~

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 19.999999998 / 60