Submission #15898

#	Time	Username	Problem	Language	Result	Execution time	Memory
15898		ggoh	Dreaming (IOI13_dreaming)	C++98	100 / 100	100 ms	12664 KiB

dreaming

#include<cstdio>
#include<vector>
#include<algorithm>
#include "dreaming.h"
struct AA{
	int to,cost;
};
std::vector<AA>G[100002];
int ans,i,m,t,st[100002],back[100002],backlen[100002],pos,len,K;
bool v[100002],vv[100002];
void dfs(int x,int l)
{
	for(int j=0;j<G[x].size();j++)
	{
		AA u=G[x][j];
		if(!v[u.to])
		{
			if(m<=l+u.cost)
			{
				pos=u.to;m=l+u.cost;
			}
			v[u.to]=1;
			dfs(u.to,l+u.cost);
		}
	}
}
void dfs2(int x,int l)
{
	for(int j=0;j<G[x].size();j++)
	{
		AA u=G[x][j];
		if(!vv[u.to])
		{
			if(m<=l+u.cost)
			{
				pos=u.to;m=l+u.cost;
			}
			
			vv[u.to]=1;
			dfs2(u.to,l+u.cost);
		}
		else back[x]=u.to,backlen[x]=u.cost;
	}
}
int travelTime(int N, int M, int L, int* A, int* B, int* T)
{

	for(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(i=1;i<=N;i++)
	{
		if(!v[i])
		{
			v[i]=1;
			m=0;
			pos=i;
			dfs(i,0);
			m=0;
			back[pos]=-1;
			vv[pos]=1;
			dfs2(pos,0);
			len=std::max(len,m);
			K=0;st[t]=m;
			while(back[pos]!=-1)
			{
				K+=backlen[pos];
				st[t]=std::min(st[t],std::max(K,m-K));
				pos=back[pos];
			}
			t++;
		}
	}
	if(t==1)ans=std::max(st[0],len);
	else if(t==2)ans=std::max(st[0]+st[1]+L,len);
	else 
	{
		std::sort(st,st+t);
		int m1=st[t-1],m2=st[t-2],m3=st[t-3];
		ans=std::max(len,m1+L+m2);
		ans=std::max(ans,m2+2*L+m3);
	}
	return ans;
}

Compilation message (stderr)

dreaming.cpp: In function 'void dfs(int, int)':
dreaming.cpp:13:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<G[x].size();j++)
              ~^~~~~~~~~~~~
dreaming.cpp: In function 'void dfs2(int, int)':
dreaming.cpp:29:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<G[x].size();j++)
              ~^~~~~~~~~~~~

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