Submission #1235748

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235748		MuhammadSaram	Thousands Islands (IOI22_islands)	C++20	24 / 100	48 ms	9800 KiB

islands

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

using namespace std;

const int M = 1000;

vector<int> nei[M],ans;
map<pair<int,int>,int> ind; 
int vis[M], par[M];

void dfs(int u)
{
	vis[u]=1;
	if (ans.size()) return;
	for (int i:nei[u])
	{
		if (!vis[i])
			par[i]=u,dfs(i);
		else if(vis[i]==1)
		{
			int v=u;
			while (v)
				ans.push_back(ind[{par[v],v}]),v=par[v];
			reverse(ans.begin(),ans.end());
			ans.push_back(ind[{u,i}]);
			v=u;
			vector<int> c;
			while (v!=i)
				c.push_back(ind[{par[v],v}]),v=par[v];
			reverse(c.begin(),c.end());
			c.push_back(ind[{u,i}]);
			for (int x:c)
				ans.push_back(x+1);
			reverse(c.begin(),c.end());
			for (int x:c)
				ans.push_back(x);
			for (int x:c)
				ans.push_back(x+1);
			v=i;
			while (v)
				ans.push_back(ind[{par[v],v}]),v=par[v];
		}
		if (ans.size()) return;
	}
	vis[u]=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)
		nei[U[i]].push_back(V[i]),ind[{U[i],V[i]}]=i;
	dfs(0);
	if (ans.size()) return ans;
	return false;
}

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