Submission #1065580

#	Time	Username	Problem	Language	Result	Execution time	Memory
1065580		ReLice	Longest Trip (IOI23_longesttrip)	C++17	5 / 100	1016 ms	1552 KiB

longesttrip

#include "longesttrip.h"
#include <bits/stdc++.h>
#define ll int
#define pb push_back
#define ins insert
#define fr first
#define sc second
#define vll vector<ll>
#define sz size()
using namespace std;

const ll N = 260;
const ll inf = 1e9 + 7;

vector<vll> g(N);
ll d[N],p[N];
bool vis[N];

void dfs(ll v){
	vis[v] = 1;
	for(auto i : g[v]){
		if(d[i] != inf || (!vis[i] && d[i] < d[v] + 1))continue;
		
		p[i] = v;
		d[i] = d[v] + 1;
		
		dfs(i);
	}
	vis[v] = 0;
}

void cl(){
	for(ll i=0;i<N;i++){
		d[i] = inf;
		p[i] = i;
	}
}

pair<ll,ll> find(){
	ll mx = -1, x = 0;
	
	for(ll i=0;i<N;i++){
		if(d[i] != inf && d[i] > mx){
			mx = d[i];
			x = i;
		}
	}
	
	return {mx, x};
}

vector<int> longest_trip(int n, int D){
	ll i,j;
	
	for(i=0;i<n;i++) g[i].clear();
	for(i=0;i<n;i++){
		for(j=i+1;j<n;j++){
			if(are_connected({i},{j})){
				g[i].pb(j);
				g[j].pb(i);
			}
		}
	}
	
	ll rt = 0, ans = 0;
	
	for(i=0;i<n;i++){
		cl();
		
		d[i] = 0;
		dfs(i);
		
		auto [mx, x] = find();
		
		if(mx < ans){
			mx = ans;
			rt = i;
		}
	}
	
	cl();
	
	d[rt] = 0;
	dfs(rt);
	
	auto [mx, x] = find();
	
	vll v;
	while(x != rt){
		v.pb(x);
		x = p[x];
	}
	v.pb(rt);
	
	return v;
}

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 25
• Subtask 4: 0 / 60