Submission #31788

#	Time	Username	Problem	Language	Result	Execution time	Memory
31788		Diuven	Dreaming (IOI13_dreaming)	C++11	100 / 100	205 ms	15964 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
typedef struct {int to, cost;} edge;
vector<edge> G[100010], T(100010);
vector<int> rad;
bool done[100010];
int N, M, L, tmp, sz[100010], u, D;
int find(int v, bool trace=false, int p=-1, int d=0){
	done[v]=true;
	if(tmp<d)	tmp=d, u=v;
	int mx=0;
	for(auto& e:G[v]){
		if(e.to==p)	continue;
		int down=find(e.to, false, v, d+e.cost)+e.cost;
		if(down>mx)	mx=down, T[v]=e;
	}
	return mx;
}
int findcen(int v){
	tmp=-1, find(v); int a=u;
	tmp=-1, T.clear(), find(a,true); int b=u, dia=tmp, now=0;
	while(a!=b){
		int nxt=now+T[a].cost;
		if(nxt<=dia-nxt){
			a=T[a].to, now=nxt;	continue;
		}
		if(max(now, dia-now)>max(nxt, dia-nxt))
			a=T[a].to;
		break;
	}
	return a;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
	for(int i=0; i<M; i++){
		G[A[i]+1].push_back({B[i]+1, T[i]});
		G[B[i]+1].push_back({A[i]+1, T[i]});
	}
	for(int i=1; i<=N; i++)
		if(!done[i]){
			int c=findcen(i);
			tmp=-1, find(c), rad.push_back(tmp);
			tmp=-1, find(u), D=max(D, tmp);
		}
	sort(rad.begin(), rad.end(), greater<int>());
	if(rad.size()>1U)	D=max(D, rad[0]+rad[1]+L);
	if(rad.size()>2U)	D=max(D, rad[1]+rad[2]+2*L);
	return 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