Submission #1052351

#	Time	Username	Problem	Language	Result	Execution time	Memory
1052351		Zicrus	Longest Trip (IOI23_longesttrip)	C++17	5 / 100	3060 ms	547716 KiB

longesttrip

#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;
 
typedef long long ll;
 
vector<vector<ll>> adj, noAdj;
vector<bool> vst;
vector<vector<ll>> k;

void dfs(ll cur, ll comp) {
    vst[cur] = true;
    k[comp].push_back(cur);
    for (auto &e : noAdj[cur]) {
        if (vst[e]) continue;
        dfs(e, !comp);
    }
}
 
vector<int> longest_trip(int n, int d) {
    adj = vector<vector<ll>>(n);
    noAdj = vector<vector<ll>>(n);
    vector<vector<bool>> mat(n, vector<bool>(n));
    for (int i = 0; i < n; i++) {
        for (int j = i+1; j < n; j++) {
            if (are_connected({i}, {j})) {
                adj[i].push_back(j);
                adj[j].push_back(i);
                mat[i][j] = true;
                mat[j][i] = true;
            }
            else {
                noAdj[i].push_back(j);
                noAdj[j].push_back(i);
            }
        }
    }

    mt19937 mt(943260);
    vector<int> G(n);
    for (int i = 0; i < n; i++) G[i] = i;
    help:
    shuffle(G.begin(), G.end(), mt);
    k = vector<vector<ll>>(2);

    vst = vector<bool>(n);
    ll comp = 0;
    for (int i1 = 0; i1 < n; i1++) {
        int i = G[i1];
        if (vst[i]) continue;
        dfs(i, comp);
        comp = !comp;
    }
    if (k[0].size() < k[1].size()) swap(k[0], k[1]);

    ll mxDeg = 0, bridge = 0;
    for (int i = 0; i < k[0].size(); i++) {
        if (adj[k[0][i]].size() > mxDeg) {
            mxDeg = adj[k[0][i]].size();
            bridge = i;
        }
    }

    vst = vector<bool>(n);
    vector<int> res;
    for (int i = bridge+1; i < k[0].size(); i++) {
        vst[k[0][i]] = true;
        res.push_back(k[0][i]);
    }
    for (int i = 0; i <= bridge; i++) {
        vst[k[0][i]] = true;
        res.push_back(k[0][i]);
    }
    ll used = -1;
    for (auto &e : adj[k[0][bridge]]) {
        if (vst[e]) continue;
        used = e;
        break;
    }
    if (used == -1) return res;
    for (int i = 0; i < k[1].size(); i++) {
        if (k[1][i] == used) {
            used = i;
            break;
        }
    }
    for (int i = used; i < k[1].size(); i++) {
        res.push_back(k[1][i]);
    }
    for (int i = 0; i < used; i++) {
        res.push_back(k[1][i]);
    }

    for (int i = 1; i < res.size(); i++) {
        if (!mat[i-1][i]) goto help;
    }

    return res;
}

Compilation message (stderr)

longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:57:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |     for (int i = 0; i < k[0].size(); i++) {
      |                     ~~^~~~~~~~~~~~~
longesttrip.cpp:58:33: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
   58 |         if (adj[k[0][i]].size() > mxDeg) {
      |             ~~~~~~~~~~~~~~~~~~~~^~~~~~~
longesttrip.cpp:66:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for (int i = bridge+1; i < k[0].size(); i++) {
      |                            ~~^~~~~~~~~~~~~
longesttrip.cpp:81:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |     for (int i = 0; i < k[1].size(); i++) {
      |                     ~~^~~~~~~~~~~~~
longesttrip.cpp:87:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |     for (int i = used; i < k[1].size(); i++) {
      |                        ~~^~~~~~~~~~~~~
longesttrip.cpp:94:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   94 |     for (int i = 1; i < res.size(); i++) {
      |                     ~~^~~~~~~~~~~~

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