Submission #744398

#	Time	Username	Problem	Language	Result	Execution time	Memory
744398		MODDI	Dreaming (IOI13_dreaming)	C++14	100 / 100	191 ms	28932 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
#define ll long long
#define mp make_pair
#define pb push_back
using namespace std;
vector<vector<pair<int, int> > > G;
vector<bool> vis;
ll ans, help = 0;
void dfs(int at, int parent, long long dist, vector<pair<int, long long> >& paths){
	vis[at] = true;
	paths.push_back(make_pair(at, dist));
	for(auto next : G[at]){
		if(next.first != parent){
			dfs(next.first, at, dist + next.second, paths);
		}
	}
}
void solve(int start){
	vector<pair<int, ll> > d, d2;
	dfs(start,start, 0, d);
	ll len1 = -1;
	int node1;
	for(auto t : d){
		if(len1 < t.second){
			len1 = t.second;
			node1 = t.first;
		}
	}
	d.clear();
	dfs(node1,node1, 0, d);
	ll len2 = -1;
	int node2;
	map<int,ll> store;
	for(auto t : d){
		store[t.first] = t.second;
		if(len2 < t.second){
			len2 = t.second;
			node2 = t.first;
		}
	}
	help = max(help, len2);
	dfs(node2,node2, 0, d2);
	for(auto t : d2){
		ans = min(ans, max(t.second, store[t.first]));
	}
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	vis.resize(N, false);
	G.resize(N);
    for(int i = 0; i < M; i++){
    	G[A[i]].pb(mp(B[i], T[i]));
    	G[B[i]].pb(mp(A[i], T[i]));
	}
	vector<ll> arr;
	for(int i = 0; i < N; i++){
		if(!vis[i]){
			ans = 2e9;
			solve(i);
			arr.pb(ans);			
		}
		else
			continue;
	}
	sort(arr.rbegin(), arr.rend());
	if(arr.size() == 1)	return max(arr[0], help);
	else if(arr.size() == 2)
		return max(help, arr[0] + arr[1] + L);
	else
		return max(max(arr[0] + arr[1] + L, arr[1] + arr[2] + 2 * L), help);
}

Compilation message (stderr)

dreaming.cpp: In function 'void solve(int)':
dreaming.cpp:43:5: warning: 'node2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   43 |  dfs(node2,node2, 0, d2);
      |  ~~~^~~~~~~~~~~~~~~~~~~~
dreaming.cpp:31:5: warning: 'node1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   31 |  dfs(node1,node1, 0, d);
      |  ~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23