Submission #106325

#	Time	Username	Problem	Language	Result	Execution time	Memory
106325		ly20	Dreaming (IOI13_dreaming)	C++14	0 / 100	100 ms	20344 KiB

dreaming

#include<bits/stdc++.h>
#include "dreaming.h"
using namespace std;
#define debug(args...) fprintf(stderr,args)
const int MAXN=112345,INF=1123456789;
vector<int> grafo[MAXN],peso[MAXN];
vector<int> rs;
int maxdist,id,dist[MAXN][2],marc[MAXN][3],rmin,pai[MAXN],pspai[MAXN];

int md;
void dfs1(int v)
{
	marc[v][0]=1;
	if(dist[v][0]>maxdist)
	{
		maxdist=dist[v][0];
		id=v;
	}
	for(int i=0;i<grafo[v].size();i++)
	{
		int viz=grafo[v][i],p=peso[v][i];
		if(marc[viz][0]==1)continue;
		dist[viz][0]=dist[v][0]+p;
		dfs1(viz);
	}
}
void dfs2(int v)
{
	marc[v][1]=1;
	if(dist[v][1]>maxdist)
	{
		maxdist=dist[v][1];
		id=v;
	}
	for(int i=0;i<grafo[v].size();i++)
	{
		int viz=grafo[v][i],p=peso[v][i];
		if(marc[viz][1]==1)continue;
		pai[viz]=v;
		pspai[viz]=p;
		dist[viz][1]=dist[v][1]+p;
		dfs2(viz);
	}
}
int travelTime(int N,int M,int L,int A[],int B[],int T[])
{
	int n=N,m=M,l=L,a[m],b[m],t[m];
	for(int i=0;i<m;i++)
	{
		a[i]=A[i];b[i]=B[i];t[i]=T[i];
	}
	for(int i=0;i<m;i++)
	{
		grafo[a[i]].push_back(b[i]);grafo[b[i]].push_back(a[i]);
		peso[a[i]].push_back(t[i]);peso[b[i]].push_back(t[i]);	
	}
	int nmc=n-m;
	md=0;maxdist=0;id=0;
	int resp=0;
	for(int i=0;i<nmc;i++)
	{
		if(marc[i][0]==0)
		{
			maxdist=0;
			dfs1(i);
			maxdist=0;
			pai[id]=id;
			pspai[id]=0;
			dfs2(id);
			md=max(md,maxdist);
			int dm=maxdist,dm1=maxdist;
			maxdist=INF;
			while(pai[id]!=id)
			{
				int k=max(dm1,dm-dm1);
				maxdist=min(maxdist,k);
				dm1-=pspai[id];
				id=pai[id];
			}
			rs.push_back(maxdist);
		}
	}
	sort(rs.begin(),rs.end());
	int tm=rs.size();
	resp=0;
	resp=max(resp,md);
	if(tm>=2)resp=max(resp,rs[tm-1]+rs[tm-2]+l);
	if(tm>=3)resp=max(resp,rs[tm-2]+rs[tm-3]+2*l);
	return resp;
}
/*int n,m,l,a[MAXN],b[MAXN],t[MAXN];
int main()
{
	scanf("%d %d %d",&n,&m,&l);
	for(int i=0;i<m;i++)scanf("%d %d %d",&a[i],&b[i],&t[i]);
	printf("%d\n",travelTime(n,m,l,a,b,t));
	return 0;
}*/

Compilation message (stderr)

dreaming.cpp: In function 'void dfs1(int)':
dreaming.cpp:19:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<grafo[v].size();i++)
              ~^~~~~~~~~~~~~~~~
dreaming.cpp: In function 'void dfs2(int)':
dreaming.cpp:35:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<grafo[v].size();i++)
              ~^~~~~~~~~~~~~~~~

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