很简单的一道广度遍历题目

1 #include 
     
        2 #define up_bound 100000  3 #define down_bound 0  4 int Q[100010],dist[100010]={
   0};  5 int vis[100010]={
   0};  6  7 int bfs(int n,int k){
    8     int front=0,rear=1;  9     Q[front]=n; 10     vis[n]=1; 11     while(front
      
       down_bound){
   16             vis[x-1]=1; 17             dist[rear]=dist[front]+1; 18             Q[rear++]=x-1; 19         } 20         if(vis[x+1]==0 && x
       
        down_bound && x<=up_bound/2){
   26             vis[2*x]=1; 27             dist[rear]=dist[front]+1; 28             Q[rear++]=2*x; 29         } 30         front++; 31     } 32     return dist[front]; 33 } 34 int main(){
   35     int N,K,ans; 36     scanf("%d %d",&N,&K); 37     if(N>K) ans=N-K;      38     else ans=bfs(N,K); 39     printf("%d\n",ans); 40 }