Implemented with fixed length array queue stack and

Stack: last out

Pankongpanman

push

pop

peek

public class ArrayStack {
    private Integer index;//把新来的数加入index上
    private Integer[] arr;
    public ArrayStack(int initSize){
        if(initSize==0) {
            throw new IllegalArgumentException("less than 0");
        }
       arr=new Integer[initSize];
    }
    public  void  push(int a){
        if(index==arr.length){
            throw new ArrayIndexOutOfBoundsException("栈满") ;
        }
        arr[index++]=a;

    }
    public  Integer  pop(){
        if(index==0){
            throw new ArrayIndexOutOfBoundsException("空栈") ;
        }
        return arr[--index];

    }
    public  Integer  peek(){
        if(index==0){
            throw new ArrayIndexOutOfBoundsException("空栈") ;
        }
        return arr[index-1];

    }

}

 

Queue: FIFO

start (size is not 0) to which an unknown number of pick up, start of arr.length-1, and szie = arr.legth;! start zero

end (and about the size, size dissatisfaction) plus, end to arr.length-1, and szie! = arr.legth, end-zero

size: not greater than the length of the array

push (): focus on end and size

poll (): focus on start and size

 

public class ArrayQueue {
    private int end;
    private int start;
    private int size;
    private Integer[] arr;

    public ArrayQueue(int initSize){
        if(initSize==0){
            throw  new IllegalArgumentException("less than 0");
        }
        end=0;
        start=0;
        size=0;
        arr=new Integer[initSize];
    }


    public Integer pop(){
     if(size==0){
         throw new ArrayIndexOutOfBoundsException("空");
     }
        size--;
     int ret=start;
     start=start==arr.length-1?0:start+1;
       return arr[ret];

    }
    public void push(int a){
      if(size==arr.length){
          throw new ArrayIndexOutOfBoundsException("队列满");
      }
      arr[end]=a;
      size++;
      end=end==arr.length-1?0:end+1;
    }
    public int peek(){
        if (size==0) throw new ArrayIndexOutOfBoundsException("空");
      return arr[start];
    }
}