Submission #715597

#	Time	Username	Problem	Language	Result	Execution time	Memory
715597		Baytoro	Dreaming (IOI13_dreaming)	C++17	100 / 100	74 ms	16360 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
#define fr first
#define sc second
const int N=1e5+5;
vector<pair<int,int>> g[N];
int used[N],d[N];
pair<int,int> par[N];
vector<int> vec;
int ans=0;
int D,f;
void dfs(int x, int p){
	used[x]=1;
	if(p==x){
		d[x]=0;
		D=0,f=x;
	}
	else{
		if(d[x]>D){
			D=d[x];
			f=x;
		}
	}
	for(auto it: g[x]){
		if(it.fr==p) continue;
		d[it.fr]=it.sc+d[x];
		par[it.fr]={x,it.sc};
		dfs(it.fr,x);
	}
}
 
void find(int x){
	dfs(x,x);
	int a=f;
	dfs(a,a);
	int b=f;
	ans=max(ans,D);
	if(a==b){
		vec.push_back(0);
		return;
	}
	int cur=b,d=0;
	while(true){
		int last=d;
		d+=par[cur].sc;
		cur=par[cur].fr;
		if(2*d>=D){
			vec.push_back(min(D-last,d));
			return;
		}
	}
}
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]});
	}
	for(int i=0;i<N;i++){
		if(!used[i]){
			find(i);
		}
	}
	sort(vec.rbegin(),vec.rend());
	if(vec.size()>1)
		ans=max(ans,vec[0]+vec[1]+L);
	if(vec.size()>2)
		ans=max(ans,vec[1]+vec[2]+L+L);
	return ans;
}

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