【转】POJ-3278 Catch That Cow:BFS

#include<iostream>
#include<queue>
#include<cstring>
using namespace std;

struct node
{
        int Value, Steps;
        node( int N, int S ): Value(N), Steps(S){}
};

queue<node>Que;
int Visited[100000];

int main()
{
        int N, K;
        memset( Visited, 0, sizeof(Visited) );
        cin>>N>>K;
        Que.push(node(N,0));
        Visited[N] = 1;
        while( !Que.empty() )
        {
                node Top = Que.front();
                if( Top.Value == K )
                {
                        cout<<Top.Steps<<endl;
                        break;
                }
                if( Top.Value-1>=0 && Visited[Top.Value-1]==0 )
                {
                        Que.push( node(Top.Value-1, Top.Steps+1) );
                        Visited[Top.Value-1] = 1;
                }
                if( Top.Value+1<=100000 &&Visited[Top.Value+1]==0 )
                {
                        Que.push( node(Top.Value+1, Top.Steps+1) );
                        Visited[Top.Value+1] = 1;
                }
                if( Top.Value*2<=100000 &&Visited[Top.Value*2]==0 )
                {
                        Que.push( node(Top.Value*2, Top.Steps+1) );
                        Visited[Top.Value*2] = 1;
                }
                Que.pop();
        }
        return 0;
}