Submission #684107

#	Time	Username	Problem	Language	Result	Execution time	Memory
684107		fuad27	Dreaming (IOI13_dreaming)	C++17	100 / 100	134 ms	30932 KiB

dreaming

#include "dreaming.h"
#include<bits/stdc++.h>
using namespace std;
const int N = 100'010;
vector<array<int,2>> g[N];
vector<int> vis;
int d[N];
int cnt=0,res=0;
void dist(int at, int p) {
	vis[at]=1;
	d[at]=0;
	for(auto to:g[at]) {
		if(to[0]==p)continue;
		dist(to[0],at);
		d[at]=max(d[to[0]]+to[1],d[at]);
	}
}

void dfs(int at, int dd) {
	vis[at]=cnt;
	d[at]=max(d[at],dd);
	res=max(res,d[at]);
	res=max(res,d[at]);
	multiset<int> ms;
	for(auto to:g[at]) {
		if(vis[to[0]])continue;
		ms.insert(d[to[0]]+to[1]);
	}
	ms.insert(dd);
	for(auto to:g[at]) {
		if(vis[to[0]])continue;
		int tmp=d[to[0]]+to[1];
		ms.erase(ms.find(tmp));
		dfs(to[0],(*(--ms.end()))+to[1]);
		ms.insert(tmp);
	}
}
int travelTime(int n, int m, int l, int a[], int b[], int t[]) {
	for(int i = 0; i<m; i++){
		g[a[i]].push_back({b[i],t[i]});
		g[b[i]].push_back({a[i],t[i]});
	}
	vis.resize(n);
	for(int i = 0;i<n;i++) {
		if(!vis[i])
		dist(i,-1);
	}
	for(int i = 0;i<n;i++){vis[i]=0;}
	for(int i =0 ;i<n;i++) {
		if(!vis[i]) {
			++cnt;
			dfs(i,0);
		}
	}
	vector<int> v(n+1,2e9);
	for(int i = 0;i<n;i++){
		v[vis[i]]=min(v[vis[i]],d[i]);
	}
	vector<int> aa;
	for(int i = 1;i<=n;i++) {
		if(v[i]!=2e9)aa.push_back(v[i]);
	}
	sort(aa.begin(),aa.end());
	if(aa.size()>=2)res=max(res,aa.back()+aa[aa.size()-2]+l);
	aa.pop_back();
	if(aa.size()>=2)res=max(res,aa.back()+aa[aa.size()-2]+l+l);
	return res;
}

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