栈/两个栈实现一个队列

た入场券 2021-09-23 07:02 407阅读 0赞

### Java实现 ###

/*
    *
     * @auther: 巨未
     * @DATE: 2019/1/5 0005 18:29
     * @Description:  顺序栈
    
    */
    
    class MyStackK {
        private int[] elem;
        private int top;
    
        public MyStackK() {
            this(10);
        }
    
        public MyStackK(int size) {
            this.elem = new int[size];
            this.top = 0;
        }
    
    //入栈
    
        public void push(int val) {
            if (isFull()) {
                return;
            }
            this.elem[this.top++] = val;  //放一个值，top+1
        }
    
    //出栈
    
        public void pop() {
            if (isEmpty()) {
                return;
            }
            this.top--;
        }
    
    //判满
    
        public boolean isFull() {   //top是否等于数组elem的长度
            if (this.top == this.elem.length) {
                return true;
            }
            return false;
        }
    
    //判空
    
        public boolean isEmpty() {
            if (this.top == 0) {
                return true;
            }
            return false;
        }
    
    //得到栈顶元素
    
        public int getTop() {
            if (isEmpty()) {
                throw new UnsupportedOperationException("栈为空！");
            }
             return this.elem[this.top-1];
        }
    
    //得到栈顶元素并且删除
    
        public int getTop1() {
            if (isEmpty()) {
                throw new UnsupportedOperationException("栈为空！");
            }
          int data = this.elem[this.top-1];
            return data;
    }
    //打印栈内元素
    
        public void show(){
            for(int i = 0;i < this.top;i++){
                System.out.print(this.elem[i] +" ");
            }
        }
    
    }
    
    public class CStackDemo {
    /*
    *
         * 两个栈实现一个队列： 入队
         * @param s1
         * @param val
    
    */
    
        public static void pushQueue(MyStackK s1, int val) {
            //先入栈：
             s1.push(val);
        }
    
    /**
         *两个栈实现一个队列： 出队
         * @param s1
         * @param s2
         * @return
         */
    
        public static int popQueue(MyStackK s1, MyStackK s2) {
            //把所有数据放到s2
            if (s2.isEmpty()) {
                int tmp = 0;
                while (!s1.isEmpty()) {
                    tmp = s1.getTop();
                    s2.push(tmp);
                }
            }
            //将s2栈顶元素出栈
            int tmp2 = 0;
            if (!s2.isEmpty()) {
                tmp2 = s2.getTop();
            }else {
                System.out.println("队列为空！");
            }
            return tmp2;
    
        }
    
    
        public static void main(String[] args) {
          MyStackK myStackK = new MyStackK();
          myStackK.push(1);
          myStackK.push(2);
          myStackK.push(4);
          myStackK.push(9);
          myStackK.push(3);
          myStackK.pop();
            System.out.println(myStackK.getTop());
            myStackK.show();
    
        }
    }