栈和队列

来源：互联网发布：马曳知乎编辑：程序博客网时间：2024/06/06 11:36

public class Queue {    private Element head;    private Element tail;    public int size;    public void enqueue(Element e){        if(tail == null){            head = e;            tail = e;        }else{            tail.next = e;            tail = e;        }        size++;    }    public Element dequeue(){        if(head == null){            return null;        }else{            Element p = head;            head = head.next;            p.next = null;            if(head == null){                tail = null;            }            size--;            return p;        }    }}

public class Stack {    public Element top;    public int sum;    public Element pop(){        if(top == null){            return null;        }else{            Element p = top;            sum -= top.value;            top = top.next;            p.next = null;            return p;        }    }    public void push(Element e){        if(top == null){            top = e;        }else{            e.next = top;            top = e;        }        sum += e.value;    }}

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