剑指Offer 面试题5 从尾到头打印链表

                                           剑指Offer 面试题5 从尾到头打印链表

       本文题目来自《剑指offer 名企面试官精讲典型编程题》面试题5。

       题目5：输入一个链表的头结点，从尾到头反过来打印每个结点的值。

       思路:从头到尾遍历一遍链表，将每个结点顺次压入栈中。遍历完链表后，再从栈顶开始逐个输出结点的值。代码中的链表插入方法为头插法。具体头插法的介绍详见：http://blog.csdn.net/wp1603710463/article/details/50989500

       Java实现代码：

       1.SingleLinkList:

package list;

import java.util.HashSet;
import java.util.Set;

/**
 * @author WuPing
 * @version 2016年4月11日 上午10:41:43
 */

public class SingleLinkList {

    class Element {
	public Value value = null;
	public Element nextNode = null;
    }

    class Value {
	public long code;
	public String name;

	public Value() {
	}

	public Value(long code, String name) {
	    this.code = code;
	    this.name = name;
	}

	@Override
	public String toString() {
	    return code + "-" + name;
	}
    }

    private Element header = null;

    public void add(Value node) {
	if (header == null) {
	    header = new Element();
	    header.value = null;
	    header.nextNode = null;
	}
	Element element = new Element();
	element.value = node;
	element.nextNode = header.nextNode;
	header.nextNode = element;
    }

    public void clear() {
	header = null;
    }

    public boolean contains(Object o) {
	if (header == null)
	    return false;
	Element eqEl = header.nextNode;
	while (eqEl != null) {
	    if (eqEl.value == o) {
		return true;
	    }
	    eqEl = eqEl.nextNode;
	}
	return false;
    }

    public String toString() {
	int size = this.size();
	String print = "";
	if (size == 0)
	    return print;
	for (int i = 0; i < size; i++) {
	    print = "," + this.get(i) + print;
	}
	print = "[" + print.substring(1) + "]";
	return print;
    }

    public Object get(int index) {
	if (header == null)
	    return null;
	int size = this.size();
	if (index > (size - 1) || index < 0) {
	    return null;
	}
	Element temp = header.nextNode;
	int i = 0;
	while (temp != null) {
	    if (index == i) {
		return temp.value;
	    }
	    i++;
	    temp = temp.nextNode;
	}
	return null;
    }

    public String getValueName(int index) {
	if (header == null)
	    return "";
	int size = this.size();
	if (index > (size - 1) || index < 0) {
	    return "";
	}
	Element temp = header.nextNode;
	int i = 0;
	while (temp != null) {
	    if (index == i) {
		return temp.value.name;
	    }
	    i++;
	    temp = temp.nextNode;
	}
	return "";
    }
    
    private Element getElement(int index) {
	if (header == null)
	    return null;
	int size = this.size();
	if (index > (size - 1) || index < 0) {
	    return null;
	}
	Element temp = header.nextNode;
	int i = 0;
	while (temp != null) {
	    if (index == i) {
		return temp;
	    }
	    i++;
	    temp = temp.nextNode;
	}
	return null;
    }

    public boolean isEmpty() {
	if (header == null)
	    return true;
	else
	    return false;
    }

    public boolean remove(Object o) {
	if (header == null)
	    return false;
	Element eqPreEl = header;
	Element eqEl = header.nextNode;
	while (eqEl != null) {
	    if (eqEl.value == o) {
		eqPreEl.nextNode = eqEl.nextNode;
		return true;
	    }
	    eqPreEl = eqEl;
	    eqEl = eqEl.nextNode;
	}
	return false;
    }

    public int size() {
	if (header == null)
	    return 0;
	Element temp = header.nextNode;
	int i = 0;
	while (temp != null) {
	    i++;
	    temp = temp.nextNode;
	}
	return i;
    }

    // 检查环状单链表
    public boolean checkLoop() {
	if (header == null)
	    return false;
	int size = this.size();
	if (size == 0)
	    return false;
	Set set = new HashSet();
	for (int i = 0; i < size; i++) {
	    Element el = getElement(i);
	    if (!set.contains(el)) {
		set.add(el);
	    }
	    if (set.contains(el.nextNode)) {
		return true;
	    }
	}
	return false;
    }

}

      2.TestSingleLinkList:

package list;

import list.SingleLinkList;
import list.SingleLinkList.Value;

import java.util.Stack;

/**
 * @author WuPing
 * @version 2016年4月11日 上午10:53:00
 */

public class TestSingleLinkList {

    public static void Test1() {
	System.out.println("1.链表有多个结点：");
	SingleLinkList list = new SingleLinkList();
        Value value1 = list.new Value(1, "Java");
        Value value2 = list.new Value(2, "JavaScript");
        Value value3 = list.new Value(3, "PHP");
        Value value4 = list.new Value(4, "C++");
        Value value5 = list.new Value(5, "Python");
        Value value6 = list.new Value(6, "Swift");
        //头插法插入链表
        list.add(value1);
        list.add(value2);
        list.add(value3);
        list.add(value4);
        list.add(value5);
        list.add(value6);
        
        //用栈保存链表的结点值信息
        System.out.print("正序打印链表结点的值:");
        Stack stack = new Stack();
        for(int i=0; i stack = new Stack();
        for(int i=0; i stack = new Stack();
        for(int i=0; i

      程序运行结果截图：

       
      链表构建部分参考：

      用Java语言实现单链表：http://www.cnblogs.com/junsky/archive/2010/05/16/1736563.html