Submission #3870

#	Time	Username	Problem	Language	Result	Execution time	Memory
3870		wurikiji	Cactus? Not cactus? (kriii1_C)	C++98	0 / 1	0 ms	4072 KiB

C

#include <vector>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <string>
#include <algorithm>
#include <stack>

using namespace std;

vector<int> node[100001];
bool chk[100001];
int group[100001];
stack<int> st;

int ret;
int grp;
void dfs(int x)
{
	chk[x] = true;
	for(int i = 0 ;i < node[x].size();i++)
	{
		if( !chk[node[x][i]] ) 
			dfs(node[x][i]);
	}
	st.push(x);
}
void dfs2(int x)
{
	chk[x] = true;
	for(int i = 0 ;i < node[x].size();i++)
	{
		group[node[x][i]]++;
		if( !chk[node[x][i]] ) 
			dfs2(node[x][i]);
	}
}
int main(void){
	int n, m;

	scanf("%d %d",&n, &m);

	for(int i = 0 ;i < m ;i++)
	{
		int a, b;
		scanf("%d %d", &a, &b);
		node[a].push_back(b);
	}

	memset(chk,0,sizeof(chk));
	for(int i = 1; i <= n;i++)
	{
		if( !chk[i] ) 
			dfs(i);
	}

	memset(group, 0, sizeof(group));
	grp = 0;

	memset(chk,0,sizeof(chk));
	while(!st.empty()){
		int next = st.top();
		st.pop();
		if(!chk[next])
		{
			dfs2(next);
		}
	}
	for(int i = 1 ;i <=n;i++)
	{
		if( group[i] > 1 ) 
		{
			printf("Not cactus\n");
			return 0;
		}
	}
	printf("Cactus\n");
	return 0;
}

• Subtask 1: 0 / 1