Submission #980248

#	Time	Username	Problem	Language	Result	Execution time	Memory
980248		vjudge1	Longest Trip (IOI23_longesttrip)	C++17	5 / 100	752 ms	3060 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;
using dll = deque <ll>;
using vi = vector <int>;

const ll MAXN = 256+16;
vll adj[MAXN];
bool mat[MAXN][MAXN];
ll tvis[MAXN];
ll timer = 1;

void dfs (ll u, ll timer, ll &c) {
    if (tvis[u] == timer) return;
    tvis[u] = timer;
    c++;
    for (ll v : adj[u]) {
        dfs(v, timer, c);
    }
}

vi longest_trip (int n, int d) {
    timer++;
    fill(adj, adj+n+5, vll({}));
    for (ll u = 0; u < n; u++) {
        for (ll v = 0; v < n; v++) {
            mat[u][v] = false;
        }
    }
    for (ll u = 0; u < n; u++) {
        mat[u][u] = false;
        for (ll v = u+1; v < n; v++) {
            if (are_connected(vi({ int(u) }), vi({ int(v) }))) {
                adj[u].push_back(v);
                adj[v].push_back(u);
                mat[u][v] = true;
                mat[v][u] = true;
            } else {
                mat[u][v] = false;
                mat[v][u] = false;
            }
        }
    }
    ll c = 0;
    dfs(0, timer, c);
    if (c == n) {
        vi ans;
        ans.push_back(0);
        ll op1 = 1, op2 = 2;
        while (max(op1, op2) < n) {
            if (mat[ans.back()][op1]) {
                ans.push_back(op1);
                op1 = max(op1, op2)+1;
            } else if (mat[ans.back()][op2]) {
                ans.push_back(op2);
                op2 = max(op1, op2)+1;
            } else assert(false);
        }
        ans.push_back(min(op1, op2));
        return ans;
    } else {
        if (2*c > n) { // timer is may
            vi ans;
            for (ll u = 0; u < n; u++) {
                if (tvis[u] == timer) {
                    if(ans.size()) assert(mat[u][ans.back()]);
                    ans.push_back(u);
                }
            }
            return ans;
        } else { // timer isnt may
            vi ans;
            for (ll u = 0; u < n; u++) {
                if (tvis[u] != timer) {
                    if(ans.size()) assert(mat[u][ans.back()]);
                    ans.push_back(u);
                }
            }
            return ans;
        }
    }
}

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