Submission #83917

#	Time	Username	Problem	Language	Result	Execution time	Memory
83917		faceless	Potemkin cycle (CEOI15_indcyc)	C++17	30 / 100	187 ms	7132 KiB

indcyc

#include <bits/stdc++.h>
#define MP make_pair
#define F first
#define PB push_back
#define S second
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
const int maxn = 1e3 + 4;

vector <int> adj[maxn];
int mat[maxn][maxn];
int par[maxn];
bool mark[maxn];

void find_path (int v, int u, int w) {
	queue <int> q;
	memset (par, -1, sizeof par);
	q.push (v);
	par[v] = 0;
	while (!q.empty()) {
		int x = q.front();
		q.pop();
		for (auto y : adj[x]) {
			if (par[y] == -1 and y != u and (!mark[y] or y == w)) {
				par[y] = x;
				q.push(y);
			}
		}
	}
	while (w != 0) {
		cout << w << " ";
		w = par[w];
	}
	cout << u << endl;
	exit(0);
}

int get(int v) {
	if (par[v] == -1)
		return v;
	return par[v] = get(par[v]);
}

void merge(int v, int u) {
	v = get(v), u = get(u);
	if (v == u)
		return;
	par[v] = u;
}

pii e[100005];
int main (){
	ios_base::sync_with_stdio(false);
	int n, m;
	cin >> n >> m;
	for (int i = 0; i < m; i++) {
		int v, u;
		cin >> v >> u;
		e[i] = {v, u};
		adj[v].PB(u);
		adj[u].PB(v);
		mat[v][u] = 1;
		mat[u][v] = 1;
	}

	for (int i = 1; i <= n; i++) {
		memset (par, -1, sizeof par);
		for (auto v : adj[i]) {
			mark[v] = 1;
		}
		for (int j = 0; j < m; j++) {
			if (e[j].F != i and e[j].S != i and (!mark[e[j].F] or !mark[e[j].S])) {
				merge (e[j].F, e[j].S);
			}
		}
		for (int j = 0; j < adj[i].size(); j++) {
			for (int k = j + 1; k < adj[i].size(); k++) {
				int v = adj[i][j], u = adj[i][k];
				if (!mat[v][u] and get(v) == get(u))
					find_path (v, i, u);
			}
		}
		for (auto v : adj[i]) {
			mark[v] = 0;
		}
	}
	cout << "no" << endl;
}

Compilation message (stderr)

indcyc.cpp: In function 'int main()':
indcyc.cpp:78:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j < adj[i].size(); j++) {
                   ~~^~~~~~~~~~~~~~~
indcyc.cpp:79:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = j + 1; k < adj[i].size(); k++) {
                        ~~^~~~~~~~~~~~~~~

• 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