Submission #3499

#	Time	Username	Problem	Language	Result	Execution time	Memory
3499		Apple_Cplus	Cactus? Not cactus? (kriii1_C)	C++98	1 / 1	76 ms	12320 KiB

C

#include <stdio.h>
#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <sstream>
#include <set>
#include <map>
#include <stack>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <string>
 
using namespace std;
 
#define ll long long
#define pi pair<int,int>
#define pll pair<ll,ll>
#define pii pair<int,pi>
#define X first
#define Y second
#define pb push_back
#define ab(x) ((x)<0?(-(x)):(x))
#define xx(x) ((x)*(x))
#define mp make_pair
#define vi vector<int>
#define vll vector<ll>
#define vs vector<string>
#define vpi vector<pi>
#define vpll vector<pll>
#define ALL(x) (x).begin(),(x).end()
#define Max (1<<30)
#define LLMax (1ll<<60)
template<class T>string ToString(T t){stringstream s;s<<t;return s.str();}
template<class T>void ToOther(T&t,string a){stringstream s(a);s>>t;}
 
 
int n,m;
vi v[100005];
int dep[100005];
int P[100005];
int cy[100005];
bool ck[100005];

void go(int x,int p,int D){
	ck[x]=1;
	dep[x]=D;
	P[x]=p;
	for(int i=0;i<v[x].size();i++){
		int t=v[x][i];

		if(t==p)continue;
		if(ck[t])continue;

		go(t,x,D+1);
	}
}
void END(){cout<<"Not cactus"<<endl;exit(0);}
void calc(int a,int b){
	int D=min(dep[a],dep[b]);
	
	while(dep[a]>D){
		if(++cy[a]==2)END();
		a=P[a];
	}
	while(dep[b]>D){
		if(++cy[b]==2)END();
		b=P[b];
	}
	while(a!=b){
		if(++cy[a]==2)END();
		if(++cy[b]==2)END();
		a=P[a];b=P[b];
	}
	if(++cy[a]==2)END();

}
void dfs(int x,int p){
	ck[x]=1;
	for(int i=0;i<v[x].size();i++){
		int t=v[x][i];if(t==p)continue;
		if(ck[t]){
			if(t<x)calc(t,x);
			continue;
		}

		dfs(t,x);
	}
}
int main(){
	scanf("%d%d",&n,&m);

	for(int i=0;i<m;i++){
		int s,e;scanf("%d%d",&s,&e);
		v[s].pb(e);v[e].pb(s);

	}

	go(1,-1,0);
	memset(ck,0,sizeof(ck));
	dfs(1,-1);
	cout<<"Cactus"<<endl;
}

• Subtask 1: 1 / 1