朋友分享了一个某大厂笔试题，挺感兴趣的试做了一下

第一题

第二题

public class Test {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int base[] = {1, 4, 2, 3, 4, 3, 6, 7, 8, 9};
        while (true) {
            StringBuffer sb = new StringBuffer();
            int guest = scanner.nextInt();
            int sum = 0;
            for (int i = 0; i < base.length; i++) {
                List<Integer> tempBox = new ArrayList<>();
                sum = base[i];
                tempBox.add(base[i]);
                if (sum==guest){
                    sb.append(tempBox.toString());
                    continue;
                }
                for (int j = i+1; j < base.length; j++) {
                    tempBox.add(base[j]);
                    sum += base[j];
                    if (sum==guest) {
                        sb.append(tempBox.toString());
                    }
                }

            }
            System.out.println(sb.toString());

        }
    }

}

输出结果

第三题

package com.iamspring.first;

public class Linked<T> {

    private Node<T> first;
    private Node<T> tail;

    public Linked() {
        first = new Node<T>();
        tail = first;
    }

    public class Node<T>{
        private Node next;
        private Node pre;
        private T obj;

        public T getObj() {
            return obj;
        }

        public void setObj(T obj) {
            this.obj = obj;
        }

        public void setNext(Node next) {
            this.next = next;
        }

        public Node getPre() {
            return pre;
        }

        public void setPre(Node pre) {
            this.pre = pre;
        }
    }

    public void push(T obj){
        Node<T> node = new Node();
        node.setObj(obj);
        node.pre= tail;
        tail.next =node;
        tail = node;
    }

    public T pop(){
        if (tail.pre ==null){
            return null;
        }
        T obj = tail.getObj();
        tail = tail.pre;
        tail.next =null;
        return obj;
    }
}


测试代码

    @Test
    public void test2(){
        Linked<String> linked = new Linked<>();
        System.out.print("入栈：");
        for (int i =0;i<10;i++){
            linked.push(i+"");
            System.out.print(i+"  ");
        }
        System.out.println();
        System.out.println("出栈");
        for(int i = 0 ;i<10;i++){
            System.out.println(linked.pop());
        }
    }