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: