Submission #944550

#	Time	Username	Problem	Language	Result	Execution time	Memory
944550		4QT0R	Dreaming (IOI13_dreaming)	C++17	0 / 100	65 ms	65536 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
using namespace std;

vector<pair<int,int>> graph[100003];
int odl[100003];
int comp[100003];
vector<int> diameter[100003];
int len[100003];
int iter=0,mx_odl,mx_ver,ans=-1;

void dfs(int v, int p){
	comp[v]=iter;
	if (odl[v]>mx_odl){
		mx_odl=odl[v];
		mx_ver=v;
	}
	for (auto u : graph[v]){
		if (u.first==p)continue;
		odl[u.first]=odl[v]+u.second;
		dfs(u.first,v);
	}
}

void farthest(int v){
	mx_odl=mx_ver=-1;
	odl[v]=0;
	dfs(v,-1);
}

bool build_diameter(int v, int p, int fin){
	diameter[iter].push_back(v);
	if (v==fin)return true;
	for (auto u : graph[v]){
		if (u.first==v)continue;
		if (build_diameter(u.first,v,fin))return true;
	}
	diameter[iter].pop_back();
	return false;
}

int find_diameter(int v){
	iter++;
	farthest(v);
	int st=mx_ver;
	farthest(st);
	int nd=mx_ver;
	len[iter]=mx_odl;
	ans=max(ans,len[iter]);
	build_diameter(st,-1,nd);
	int mn=1e9+1,wyn=0;
	for (int i = 0; i<(int)diameter[iter].size(); i++){
		if (abs(mx_odl-2*odl[diameter[iter][i]])<mn){
			mn=abs(mx_odl-2*odl[diameter[iter][i]]);
			wyn=odl[i];
		}
	}
	return max(wyn,mx_odl-wyn);
}

int travelTime(int n, int m, int L, int A[], int B[], int T[]){
	for (int i = 0; i<m; i++){
		graph[A[i]].push_back({B[i],T[i]});
		graph[B[i]].push_back({A[i],T[i]});
	}
	int maxy[3]={-1,-1,-1};
	int val;
	for (int i = 0; i<n; i++){
		if (!comp[i]){
			val=find_diameter(i);
			if (val>maxy[0]){
				maxy[2]=maxy[1];
				maxy[1]=maxy[0];
				maxy[0]=val;
			}
			else if (val>maxy[1]){
				maxy[2]=maxy[1];
				maxy[1]=val;
			}
			else if (val>maxy[2]){
				maxy[2]=val;
			}
		}
	}
	if (m==1){
		ans=max(ans,maxy[0]+maxy[1]+L);
	}
	else if (m>1){
		ans=max({ans,maxy[0]+maxy[1]+L,maxy[1]+maxy[2]+2*L});
	}
	return ans;
}

• Subtask 1: 0 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23