Submission #1004754

#	Time	Username	Problem	Language	Result	Execution time	Memory
1004754		Valaki2	Potemkin cycle (CEOI15_indcyc)	C++14	100 / 100	101 ms	2204 KiB

indcyc

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

#define pb push_back

const int maxn = 1000;

int n, m;
vector<int> graph[1 + maxn];
bool matrix[1 + maxn][1 + maxn];
bool neigh[1 + maxn];
int cur_mid;
int dist[1 + maxn];
int prv[1 + maxn];
int goal;

void bfs(int start) {
    queue<int> q;
    queue<int> all;
    q.push(start);
    all.push(start);
    prv[start] = -1;
    while(!q.empty()) {
        int cur = q.front();
        q.pop();
        for(int nei : graph[cur]) {
            if(prv[nei] == 0 && (!neigh[cur] || (cur == start && !neigh[nei]))) {
                q.push(nei);
                all.push(nei);
                dist[nei] = dist[cur] + 1;
                prv[nei] = cur;
                if(nei == goal) {
                    while(nei != start) {
                        cout << nei << " ";
                        nei = prv[nei];
                    }
                    cout << start << " " << cur_mid << "\n";
                    exit(0);
                }
            }
        }
    }
    while(!all.empty()) {
        dist[all.front()] = prv[all.front()] = 0;
        all.pop();
    }
}

vector<int> this_comp;
bool been[1 + maxn];

void do_bfs(int start) {
    queue<int> q;
    q.push(start);
    been[start] = true;
    while(!q.empty()) {
        int cur = q.front();
        q.pop();
        if(neigh[cur]) {
            this_comp.pb(cur);
            continue;
        }
        for(int nei : graph[cur]) {
            if(!been[nei]) {
                q.push(nei);
                been[nei] = true;
            }
        }
    }
}

void try_for(int cur) {
    cur_mid = cur;
    if(graph[cur].empty()) {
        return;
    }
    for(int nei : graph[cur]) {
        neigh[nei] = true;
    }
    neigh[cur] = true;
    for(int i = 1; i <= n; i++) {
        if(!neigh[i] && !been[i]) {
            do_bfs(i);
            int m = (int) this_comp.size();
            for(int j = 0; j < m; j++) {
                for(int k = j + 1; k < m; k++) {
                    if(!matrix[this_comp[j]][this_comp[k]]) {
                        goal = this_comp[k];
                        bfs(this_comp[j]);
                    }
                }
            }
            for(int x : this_comp) {
                been[x] = false;
            }
            this_comp.clear();
        }
    }
    for(int nei : graph[cur]) {
        neigh[nei] = false;
    }
    neigh[cur] = false;
    for(int i = 1; i <= n; i++) {
        been[i] = false;
    }
}

void solve() {
    cin >> n >> m;
    for(int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;
        graph[a].pb(b);
        graph[b].pb(a);
        matrix[a][b] = matrix[b][a] = true;
    }
    for(int i = 1; i <= n; i++) {
        try_for(i);
    }
    cout << "no\n";
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
}

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