> # include<iostream.h>
> # include<assert.h>
> # include<math.h>
> 
> class Stack
> {
> 	public:
> 		Stack(int);
> 		~Stack() { delete[]elements;}
> 		void Push(int&);
> 		int Pop();
> 		int GetTop();
> 		void MakeEmpty() {top=-1;}
> 		int IsEmpty()const { return top==-1;}
> 		int IsFull()const { return top==maxSize-1;}
> 	private:
> 		int top;
> 		int *elements;
> 		int maxSize;
> };
> 
> Stack::Stack(int s)
> {
> 	top=-1,maxSize=s;
> 
> 	elements=new int[maxSize];
> }
> 
> void Stack::Push(int & number)
> {
> 	assert(!IsFull());
> 	elements[++top]=number;
> }
> 
> int Stack::Pop()
> {
> 	assert(!IsEmpty());
> 	return elements[top--];
> }
> 
> int Stack::GetTop()
> {
> 	if(!IsEmpty())
> 		return elements[top];
> 	else
> 		return 0;
> }
> void main()
> {
> 	int numofcoach;
> 	int i,j,sign=1;
> 	int temp;
> 	while(1)
> 	{
> 		cin>>numofcoach;
> 		if(numofcoach==0)
> 			break;		
> 		//if(sign==0)
> 			cout<<endl;
> 		/*if(sign==1)
> 			sign=0;*/
> 		while(1)
> 		{
> 			Stack *a=new Stack(numofcoach+1);
> 			Stack *b=new Stack(numofcoach);
> 			for(i=numofcoach+1;i>=1;i--)
> 				a->Push(i);
> 			for(i=0;i<numofcoach;i++)
> 			{
> 				cin>>temp;
> 				if(temp==0)
> 					break;
> 				if(temp>=a->GetTop())
> 				{
> 					for(j=a->GetTop();j<=temp;j++)
> 					{
> 						a->Pop();
> 						b->Push(j);
> 					}
> 					b->Pop();
> 				}				
> 
> 				else if(temp==b->GetTop())
> 					b->Pop();				
> 							
> 				else
> 				{
> 					for(i++;i<numofcoach;i++)
> 						cin>>temp;
> 					numofcoach--;
> 					cout<<"No"<<endl;
> 					break;
> 				}			
> 			}
> 			if(i==numofcoach)
> 				cout<<"Yes"<<endl;			
> 			delete a;
> 			delete b;
> 			if(temp==0)
> 				break;
> 		}
> 	}
> }