Submission #4150

#	Time	Username	Problem	Language	Result	Execution time	Memory
4150		pys7293	Cactus? Not cactus? (kriii1_C)	C++98	1 / 1	76 ms	15104 KiB

C

#include <algorithm>
#include <cstdio>
#include <map>
#include <memory.h>
#include <vector>

using namespace std;

int N, M;
int Lv[111111], C;
int Lo[111111];
int Chk[111111];
int P[111111];

vector<vector<int> > L;

void DFS(int i, int PP)
{
	if (Lv[i] == 0) Lv[i] = Lo[i] = ++C;
	for (int j = 0; j < L[i].size(); j++) {
		if (PP == L[i][j]) continue;
		if (Lv[L[i][j]] == 0) {
			P[L[i][j]] = i;
			DFS(L[i][j], i);
			Lo[i] = min(Lo[i], Lo[L[i][j]]);
			if (Lv[i] < Lo[L[i][j]]) Chk[L[i][j]] = true;
		} else Lo[i] = min(Lo[i], Lv[L[i][j]]);
	}
}

int main(void)
{
	scanf("%d%d", &N, &M);
	L.resize(N + 1);
	for (int i = 1; i <= M; i++) {
		int u, v;
		scanf("%d%d", &u, &v);
		L[u].push_back(v);
		L[v].push_back(u);
	}
	DFS(1, 0);
	bool Ans = true;
	for (int i = 1; i <= N; i++) {
		if (!Ans) break;
		int CC = 0;
		for (int j = 0; j < L[i].size(); j++) {
			if (i == P[L[i][j]] && Chk[L[i][j]]) continue;
			if (L[i][j] == P[i] && Chk[i]) continue;
			CC++;
		}
		if (!(CC == 0 || CC == 2)) Ans = false;
	}
	printf("%s\n", Ans ? "Cactus" : "Not cactus");

	return 0;
}

• Subtask 1: 1 / 1