제출 #1024605

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1024605		vjudge1	Thousands Islands (IOI22_islands)	C++17	1.75 / 100	28 ms	13264 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
#include <variant>

#define ll long long
#define sz(s) (int)s.size()
#define pb push_back
#define in insert
#define lb lower_bound
#define ub upper_bound
#define pii pair<int,int>
#define F first
#define S second
#define all(v) v.begin(),v.end()

using namespace std;

const int MAX=2e5+10;

vector<pii> g[MAX];
int use[MAX];
int pr[MAX];
int d[MAX];
int cycle;

void dfs(int v,int p=-1){
	pr[v]=p;
	use[v]=1;
	for(auto to:g[v]){
		// cout<<v<<" "<<pr[v]<<" "<<to.F<<" "<<to.S<<"\n";
		if(pr[v]!=-1&&to.S==(pr[v]%2==0?pr[v]+1:pr[v]-1))continue;
		if(use[to.F]){
			cycle=to.S;
			// return;
		}
		else{
			d[to.F]=d[v]+1;
			dfs(to.F,to.S);
		}
	}
	use[v]=1;
}

variant<bool, vector<int>> find_journey(int N, int M, vector<int> U,vector<int> V){
	cycle=-1;
	for(int i=0;i<M;i+=2){
		g[U[i]].pb({V[i],i});
		g[V[i]].pb({U[i],i+1});
	}
	dfs(0);
	// cout<<cycle<<"\n";
	if(cycle==-1)return false;
	return true;
	vector<int> a,b;
	int X=U[cycle],Y=V[cycle];
	while(X!=Y){
		if(d[X]>d[Y]){
			a.pb(pr[X]);
			X=U[pr[X]];
		}
		else{
			b.pb((pr[Y]%2==0?pr[Y]+1:pr[Y]-1));
			Y=U[pr[Y]];
		}
	}
	swap(a,b);
	b.pb(cycle);
	for(int x:a)b.pb(x);
	vector<int> c;
	while(X!=0){
		c.pb(pr[X]);
		X=U[pr[X]];
	}
	vector<int> ans;
	reverse(all(c));
	for(int x:c)ans.pb(x);

	for(int x:b)ans.pb(x);
	reverse(all(b));
	for(int x:b){
		ans.pb((x%2==0?x+1:x-1));
	}
	for(int x:b)ans.pb(x);
	reverse(all(b));
	for(int x:b){
		ans.pb((x%2==0?x+1:x-1));
	}

	reverse(all(c));
	for(int x:c)ans.pb(x);
	return ans;
}

• Subtask 1: 0 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45