Submission #258157

#	Time	Username	Problem	Language	Result	Execution time	Memory
258157		doowey	Potemkin cycle (CEOI15_indcyc)	C++14	30 / 100	222 ms	1404 KiB

indcyc

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int N = 1005;
const int LOG = 14;
vector<int> T[N];
bool vis[N];

int dep[N];
int cc;
int par[N];
int high[N];

void dfs(int u, int pp){
    par[u] = pp;
    vis[u]=true;
    for(auto x : T[u]){
        if(x == pp){
            continue;
        }
        if(vis[x]) {
            high[u] = max(high[u], dep[x]);
            continue;
        }
        dep[x]=dep[u]+1;
        dfs(x, u);
    }
}

int main(){
    fastIO;
    int n, m;
    cin >> n >> m;
    int u, v;
    for(int i = 0 ; i < m ; i ++ ){
        cin >> u >> v;
        T[u].push_back(v);
        T[v].push_back(u);
    }
    vector<int> pash;
    for(int i = 1; i <= n; i ++ )
        pash.push_back(i);
    for(int it = 0; it < 200; it ++ ){
        random_shuffle(pash.begin(), pash.end());
        for(int j = 1; j <= n; j ++ ){
            vis[j]=false;
            high[j]=-1;
        }
        for(auto i : pash ){
            if(vis[i]) continue;
            dfs(i,i);
        }
        int node;
        bool good;
        for(int i = 1; i <= n; i ++ ){
            for(auto x : T[i]){
                if(dep[i] - dep[x] + 1 >= 4){
                    node = i;
                    good = true;
                    while(node != x){
                        if(node == i){
                            if(high[i] > dep[x]){
                                good = false;
                                break;
                            }
                        }
                        else if(high[node] >= dep[x]){
                            good = false;
                            break;
                        }
                        node = par[node];
                    }
                    if(good){
                        node = i;
                        while(1){
                            cout << node << " ";
                            if(node == x) break;
                            node = par[node];
                        }
                        return 0;
                    }
                }
            }
        }
    }
    cout << "no\n";
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10