Submission #948767

#	Time	Username	Problem	Language	Result	Execution time	Memory
948767		thinknoexit	Longest Trip (IOI23_longesttrip)	C++17	15 / 100	776 ms	1252 KiB

longesttrip

#include <bits/stdc++.h>
#include "longesttrip.h"
using namespace std;
using ll = long long;
int n, d;
vector<int> adj2[266];
int col[266];
void dfs(int v) {
    for (auto& x : adj2[v]) {
        if (!col[x]) col[x] = 3 - col[v], dfs(x);
    }
}
vector<int> longest_trip(int N, int D) {
    n = N;
    d = D;
    vector<vector<int>> adj(n, vector<int>(n, 1));
    for (int i = 0;i < n;i++) {
        for (int j = i + 1;j < n;j++) {
            adj[i][j] = adj[j][i] = are_connected({ i }, { j });
            if (!adj[i][j]) adj2[i].push_back(j), adj2[j].push_back(i);
        }
    }
    vector<int> r1, r2;
    for (int i = 0;i < n;i++) {
        if (!col[i]) {
            col[i] = 1;
            dfs(i);
        }
        if (col[i] == 1) r1.push_back(i);
        else r2.push_back(i);
    }
    for (int i = 0;i < n;i++) adj2[i].clear(), col[i] = 0;
    if ((int)r1.size() == n) return r1; // Complete Graph
    int s1 = r1.size(), s2 = r2.size();
    for (int i = 0;i < s1;i++) {
        for (int j = 0;j < s2;j++) {
            if (adj[r1[i]][r2[j]]) {
                swap(r1[i], r1[s1 - 1]);
                swap(r2[0], r2[j]);
                vector<int> ans;
                for (auto& x : r1) ans.push_back(x);
                for (auto& x : r2) ans.push_back(x);
                return ans;
            }
        }
    }
    if (r1.size() > r2.size()) return r1;
    return r2;
}

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