P147、面试题26：复杂链表的复制

题目：请实现ComplexListNode* Clone(ComplexListNode* pHead)，复制一个复杂链表。在复杂链表中，每个结点除了有一个m_pNext指针指向下一个结点外，还有一个m_pSibing指向链表中的任意结点或者null。
struct ComplexListNode{
      int      m_nValue;
      ComplexListNode*     m_pNext;
      ComplexListNode*     m_pSibling;
}

分析思路：

第一步是根据原始链表的每个结点N创建对应的N'，但是是把N'链接在N的后面。

第二步是设置复制出来的结点的m_pSibling。假设原始链表上的N的m_pSibling指向结点S，那么其对应复制出来的N'是N的m_pNext指向的结点，同样S'也是S的m_pNext指向的结点。

第三步是把这个长链表拆分成两个链表：把奇数位置的结点用m_pNext链接起来就是原始链表，把偶数位置的结点用m_pNext链接起来就是复制出来的链表。

 

测试用例：

1）功能测试（包括结点中的m_pSibling指向结点自身，两个结点的m_pSibling形成环状结构，链表中只有一个结点）；

2）特殊输入测试（指向链表头结点的指针为null指针）。

 

代码实现：

package com.yyq;
/**
 * Created by Administrator on 2015/9/20.
 */
public class CopyComplexList {
    //第一步：复制每个结点
    public static void cloneNodes(ComplexListNode pHead){
        ComplexListNode pNode = pHead;
        while(pNode != null){
            ComplexListNode pCloned = new ComplexListNode();
            pCloned.setM_nValue(pNode.getM_nValue());
            pCloned.setM_pNext(pNode.getM_pNext());
            pNode.setM_pNext(pCloned);
            pNode = pCloned.getM_pNext();
        }
    }
    //第二步：复制m_pSibling结点
    public static void connectSiblingNodes(ComplexListNode pHead){
        ComplexListNode pNode = pHead;
        while (pNode != null){
            ComplexListNode pCloned = pNode.getM_pNext();
            if (pNode.getM_pSibling() != null){
                pCloned.setM_pSibling(pNode.getM_pSibling().getM_pNext());
            }
            pNode = pCloned.getM_pNext();
        }
    }
    //第三步：将这个长链表分成两个表
    public static ComplexListNode reconnectNodes(ComplexListNode pHead){
        ComplexListNode pNode = pHead;
        ComplexListNode pClonedHead = null;
        ComplexListNode pClonedNode = null;
        if (pNode != null){
            pClonedHead = pNode.getM_pNext();
            pClonedNode = pNode.getM_pNext();
            pNode.setM_pNext(pClonedNode.getM_pNext());
            pNode = pNode.getM_pNext();
        }
        while(pNode != null){
            pClonedNode.setM_pNext(pNode.getM_pNext());
            pClonedNode = pClonedNode.getM_pNext();
            pNode.setM_pNext(pClonedNode.getM_pNext());
            pNode = pNode.getM_pNext();
        }
        return pClonedHead;
    }
    public static ComplexListNode clone(ComplexListNode pHead){
        cloneNodes(pHead);
        connectSiblingNodes(pHead);
        return reconnectNodes(pHead);
    }
    // ====================测试代码====================
    public static void Test(String testName, ComplexListNode pHead)
    {
        if(testName != null)
            System.out.println(testName + " begins:");
        System.out.println("The original list is:");
        ComplexListNode pNode = new ComplexListNode();
        pNode.printListNode(pHead);
        ComplexListNode pClonedHead = clone(pHead);
        System.out.println("The cloned list is:");
        pNode.printListNode(pClonedHead);
    }
    //      -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//  |       |      /|\             /|\
//  --------+--------               |
//          -------------------------
    public static void Test1()
    {
        ComplexListNode pNode1 = new ComplexListNode(1);
        ComplexListNode pNode2 = new ComplexListNode(2);
        ComplexListNode pNode3 = new ComplexListNode(3);
        ComplexListNode pNode4 = new ComplexListNode(4);
        ComplexListNode pNode5 = new ComplexListNode(5);
        pNode1.buildNodes(pNode2, pNode3);
        pNode2.buildNodes(pNode3, pNode5);
        pNode3.buildNodes(pNode4, null);
        pNode4.buildNodes(pNode5, pNode2);
        Test("Test1", pNode1);
    }
    // m_pSibling指向结点自身
//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//         |       | /|\           /|\
//         |       | --             |
//         |------------------------|
    public static void Test2()
    {
        ComplexListNode pNode1 = new ComplexListNode(1);
        ComplexListNode pNode2 = new ComplexListNode(2);
        ComplexListNode pNode3 = new ComplexListNode(3);
        ComplexListNode pNode4 = new ComplexListNode(4);
        ComplexListNode pNode5 = new ComplexListNode(5);
        pNode1.buildNodes(pNode2, null);
        pNode2.buildNodes(pNode3, pNode5);
        pNode3.buildNodes(pNode4, pNode3);
        pNode4.buildNodes(pNode5, pNode2);
        Test("Test2", pNode1);
    }
    // m_pSibling形成环
//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//          |              /|\
//          |               |
//          |---------------|
    public static void Test3()
    {
        ComplexListNode pNode1 = new ComplexListNode(1);
        ComplexListNode pNode2 = new ComplexListNode(2);
        ComplexListNode pNode3 = new ComplexListNode(3);
        ComplexListNode pNode4 = new ComplexListNode(4);
        ComplexListNode pNode5 = new ComplexListNode(5);
        pNode1.buildNodes(pNode2, null);
        pNode2.buildNodes(pNode3, pNode4);
        pNode3.buildNodes(pNode4, null);
        pNode4.buildNodes(pNode5, pNode2);
        Test("Test3", pNode1);
    }
    // 只有一个结点
    public static void Test4()
    {
        ComplexListNode pNode1 = new ComplexListNode(1);
        pNode1.buildNodes(null, pNode1);
        Test("Test4", pNode1);
    }
    // 鲁棒性测试
    public static void Test5()
    {
        Test("Test5", null);
    }
    public static void main(String[] args)
    {
        Test1();
        Test2();
        Test3();
        Test4();
        Test5();
    }
}

 

结果输出：

Test1 begins:

The original list is:

The value of this node is: 1

The value of its sibling is: 3

 

The value of this node is: 2

The value of its sibling is: 5

 

The value of this node is: 3

This node does not have a sibling.

 

The value of this node is: 4

The value of its sibling is: 2

 

The value of this node is: 5

This node does not have a sibling.

 

The cloned list is:

The value of this node is: 1

The value of its sibling is: 3

 

The value of this node is: 2

The value of its sibling is: 5

 

The value of this node is: 3

This node does not have a sibling.

 

The value of this node is: 4

The value of its sibling is: 2

 

The value of this node is: 5

This node does not have a sibling.

 

Test2 begins:

The original list is:

The value of this node is: 1

This node does not have a sibling.

 

The value of this node is: 2

The value of its sibling is: 5

 

The value of this node is: 3

The value of its sibling is: 3

 

The value of this node is: 4

The value of its sibling is: 2

 

The value of this node is: 5

This node does not have a sibling.

 

The cloned list is:

The value of this node is: 1

This node does not have a sibling.

 

The value of this node is: 2

The value of its sibling is: 5

 

The value of this node is: 3

The value of its sibling is: 3

 

The value of this node is: 4

The value of its sibling is: 2

 

The value of this node is: 5

This node does not have a sibling.

 

Test3 begins:

The original list is:

The value of this node is: 1

This node does not have a sibling.

 

The value of this node is: 2

The value of its sibling is: 4

 

The value of this node is: 3

This node does not have a sibling.

 

The value of this node is: 4

The value of its sibling is: 2

 

The value of this node is: 5

This node does not have a sibling.

 

The cloned list is:

The value of this node is: 1

This node does not have a sibling.

 

The value of this node is: 2

The value of its sibling is: 4

 

The value of this node is: 3

This node does not have a sibling.

 

The value of this node is: 4

The value of its sibling is: 2

 

The value of this node is: 5

This node does not have a sibling.

 

Test4 begins:

The original list is:

The value of this node is: 1

The value of its sibling is: 1

 

The cloned list is:

The value of this node is: 1

The value of its sibling is: 1

 

Test5 begins:

The original list is:

The cloned list is: