Submission #830761

#	Time	Username	Problem	Language	Result	Execution time	Memory
830761		FatihSolak	Thousands Islands (IOI22_islands)	C++17	8.40 / 100	186 ms	30580 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
#define N 100005
using namespace std;
vector<pair<int,pair<int,int>>> adj[N];
map<int,vector<int>> mp[N];
int par[N];
int par2[N];
int vis[N];
vector<int> ans = {};
bool ok = 0;
void dfs2(int v,int pr){
	vis[v] = 1;
	vector<pair<int,pair<int,int>>> tmp;
	for(auto u:adj[v]){
		if(ok)
			return;
		if(vis[u.first] == 2){
			continue;
		}
		if(vis[u.first] == 1){
            if(ok)
                return;
            ok = 1;
            int now = u.first;
            while(now != 0){
                ans.push_back(par[now]);
                now = par2[now];
            }
            reverse(ans.begin(),ans.end());
            vector<int> v1 = {},v2 = {};
            now = v;
            int cnt = 0;
            int sz = 1;
            while(now != u.first){
                assert(cnt++ <= 1000);
                v1.push_back(par[now]);
                v2.push_back(par[now] + 1);
                sz++;
                // cout << now << endl;
                now = par2[now];
            }
            reverse(v1.begin(),v1.end());
            reverse(v2.begin(),v2.end());
            v1.push_back(u.second.first);
            v2.push_back(u.second.first + 1);
            assert(sz >= 2);
            for(int i = 0;i<sz;i++){
                for(int j = sz-i;j<sz;j++){
                    ans.push_back(v1[j]);
                }
                for(int j = 0;j<sz-i;j++){
                    ans.push_back(v1[j]);
                }
                for(int j = sz-i;j<sz;j++){
                    ans.push_back(v2[j]);
                }
                for(int j = 0;j<sz-i;j++){
                    ans.push_back(v2[j]);
                }
            }
            now = u.first;
            while(now != 0){
                ans.push_back(par[now]);
                now = par2[now];
            }
			return;
        }
		par[u.first] = u.second.first;
		par2[u.first] = v;
		dfs2(u.first,u.second.first);
	}
	vis[v] = 2;
}
variant<bool, vector<int>> find_journey(int n, int m, vector<int> U, vector<int> V){
    for(int i = 0;i<m;i+=2){
        adj[U[i]].push_back({V[i],{i,i+1}});	
        // cout << U[i] << ' ' << V[i] << endl;
    }
    dfs2(0,-1);
    if(!ok)
        return false;
    return ans;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 21
• Subtask 4: 8.399999999999999 / 24
• Subtask 5: 0 / 45