#include<iostream>
using namespace std;
int a[200000],b[100000],c[100000];
unsigned R,co,N,K,i,j;
void Rudy(int l)
{
	co++;i=0;
	if(co%2)
	for(j=1;j<=l;j++)
	{
		if(!a[2*b[j]]&&b[j]<=50002){a[2*b[j]]=1;c[++i]=2*b[j];}
		if(!a[b[j]-1]&&b[j]>=2){a[b[j]-1]=1;c[++i]=b[j]-1;}
		if(!a[b[j]+1]&&b[j]<=100002){a[b[j]+1]=1;c[++i]=b[j]+1;}
	}
	else
	for(j=1;j<=l;j++)
	{
		if(!a[2*c[j]]&&c[j]<=50002){a[2*c[j]]=1;b[++i]=2*c[j];}
		if(!a[c[j]-1]&&c[j]>=2){a[c[j]-1]=1;b[++i]=c[j]-1;}
		if(!a[c[j]+1]&&c[j]<=100002){a[c[j]+1]=1;b[++i]=c[j]+1;}
	}
	if(a[K]){cout<<co<<endl;return;}
	Rudy(i);
}
int main()
{	
	cin>>N>>K;
	if(N>=K)cout<<N-K<<endl;
	else{b[1]=N;Rudy(1);}
	return 0;
}

• Re:50题纪念 (765) linlw 2008-08-11 16:41:58
• Re:50题纪念 (765) linlw 2008-08-11 16:42:00