Submission #147232

#	Time	Username	Problem	Language	Result	Execution time	Memory
147232		luciocf	Potemkin cycle (CEOI15_indcyc)	C++14	70 / 100	1080 ms	5624 KiB

indcyc

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e3+10;

int mat[maxn][maxn];

int pai[maxn];
int dist[maxn];

bool nope[maxn];

vector<int> grafo[maxn];

void bfs(int x, int nah)
{
	memset(dist, -1, sizeof dist);

	queue<int> fila;

	fila.push(x), dist[x] = 0, pai[x] = -1;

	while (!fila.empty())
	{
		int u = fila.front(); fila.pop();

		for (auto v: grafo[u])
		{
			if (u == x && v == nah) continue;
			if (nope[v]) continue;

			if (dist[v] == -1)
			{
				dist[v] = dist[u]+1, pai[v] = u;
				fila.push(v);
			}
		}
	}
}

int main(void)
{
	int n, m;
	scanf("%d %d", &n, &m);

	for (int i = 1; i <= m; i++)
	{
		int u, v;
		scanf("%d %d", &u, &v);

		mat[u][v] = mat[v][u] = 1;

		grafo[u].push_back(v);
		grafo[v].push_back(u);
	}

	for (int u = 1; u <= n; u++)
	{
		for (auto v: grafo[u])
		{
			memset(nope, 0, sizeof nope);

			for (int w = 1; w <= n; w++)
				if (w != u && w != v && mat[w][u] && mat[w][v])
					nope[w] = 1;

			bfs(u, v);

			if (dist[v] != -1)
			{
				while (v != u)
				{
					printf("%d ", v);
					v = pai[v];
				}

				printf("%d\n", u);

				return 0;
			}
		}
	}

	printf("no\n");
}

Compilation message (stderr)

indcyc.cpp: In function 'int main()':
indcyc.cpp:45:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
indcyc.cpp:50:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~

• 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: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10