Submission #255428

#	Time	Username	Problem	Language	Result	Execution time	Memory
255428		babo	Dreaming (IOI13_dreaming)	C++14	0 / 100	90 ms	23928 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
#define LL long long

using namespace std;

vector<LL>v[100010],t[100010];
LL n,len;
LL diam;
multiset<LL>rad;

LL chk[100010];
LL ord[100010],ordend[100010],ordtop;

LL max2(LL a,LL b,LL c){
	if(a<=b&&a<=c) return b+c;
	if(b<=c&&b<=a) return c+a;
	if(c<=a&&c<=b) return a+b;
}

struct S{
	LL ma1,ma1d,ma2,ma2d;
	S(){
		ma1=ma1d=ma2=ma2d=0;
	}
	void insert(LL dist,LL loc){
		if(dist>=ma1)
		{
			ma2=ma1;
			ma2d=ma1d;
			ma1=dist;
			ma1d=loc;
		}
		else if(dist>=ma2)
		{
			ma2=dist;
			ma2d=loc;
		}
	}
}S[100010];

void dfs(LL x,LL bu){
	ordtop++;
	ord[x]=ordtop;
	LL i;
	S[x].insert(0,x);
	for(i=0;i<v[x].size();i++)
	{
		if(v[x][i]!=bu)
		{
			chk[v[x][i]]=1;
			dfs(v[x][i],x);
			S[x].insert(S[v[x][i]].ma1+t[x][i],S[v[x][i]].ma1d);
		}
	}
	diam=max(diam,S[x].ma1+S[x].ma2);
	ordend[x]=ordtop;
}

LL dfs2(LL x,LL bu,LL give){
	LL i,ret=max2(give,S[x].ma1,S[x].ma2);
	for(i=0;i<v[x].size();i++)
	{
		if(v[x][i]!=bu)
		{
			if(ord[v[x][i]]<=ord[S[x].ma1d]&&ord[S[x].ma1d]<=ordend[v[x][i]])
			{
				if(S[x].ma2d)
					ret=min(ret,dfs2(v[x][i],x,max(give+t[x][i],S[x].ma2)));
				else ret=min(ret,dfs2(v[x][i],x,give+t[x][i]));
			}
			else
				ret=min(ret,dfs2(v[x][i],x,max(give+t[x][i],S[x].ma1)));
		}
	}
	return ret;
}

void tree(LL x){
	chk[x]=1;
	dfs(x,-1);
	rad.insert(dfs2(x,-1,0));
}

int travelTime(int N,int M,int l,int A[],int B[],int T[]){
	LL i;
	n=N,len=l;
	for(i=0;i<M;i++)
	{
		v[A[i]].push_back(B[i]);
		v[B[i]].push_back(A[i]);
		t[A[i]].push_back(T[i]);
		t[B[i]].push_back(T[i]);
	}
	for(i=0;i<N;i++)
	{
		if(!chk[i])
			tree(i);
	}
	if(rad.size()==1) return (int)diam;
	else return max((int)diam,(int)(len+*prev(rad.end())+*prev(prev((rad.end())))));
}

Compilation message (stderr)

dreaming.cpp: In function 'void dfs(long long int, long long int)':
dreaming.cpp:47:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v[x].size();i++)
          ~^~~~~~~~~~~~
dreaming.cpp: In function 'long long int dfs2(long long int, long long int, long long int)':
dreaming.cpp:62:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v[x].size();i++)
          ~^~~~~~~~~~~~
dreaming.cpp: In function 'long long int max2(long long int, long long int, long long int)':
dreaming.cpp:19:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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