054_CloneComplexList.cpp

// Coding Interviews: Questions, Analysis & Solutions
// Harry He

#include <stdio.h>

struct ComplexListNode
{
    int                 m_nValue;
    ComplexListNode*    m_pNext;
    ComplexListNode*    m_pSibling;
};

void CloneNodes(ComplexListNode* pHead);
void ConnectSiblingNodes(ComplexListNode* pHead);
ComplexListNode* ReconnectNodes(ComplexListNode* pHead);

ComplexListNode* Clone(ComplexListNode* pHead)
{
    CloneNodes(pHead);
    ConnectSiblingNodes(pHead);
    return ReconnectNodes(pHead);
}

void CloneNodes(ComplexListNode* pHead)
{
    ComplexListNode* pNode = pHead;
    while(pNode != NULL)
    {
        ComplexListNode* pCloned = new ComplexListNode();
        pCloned->m_nValue = pNode->m_nValue;
        pCloned->m_pNext = pNode->m_pNext;
        pCloned->m_pSibling = NULL;
 
        pNode->m_pNext = pCloned;
        pNode = pCloned->m_pNext;
    }
}

void ConnectSiblingNodes(ComplexListNode* pHead)
{
    ComplexListNode* pNode = pHead;
    while(pNode != NULL)
    {
        ComplexListNode* pCloned = pNode->m_pNext;
        if(pNode->m_pSibling != NULL)
        {
            pCloned->m_pSibling = pNode->m_pSibling->m_pNext;
        }
 
        pNode = pCloned->m_pNext;
    }
}

ComplexListNode* ReconnectNodes(ComplexListNode* pHead)
{
    ComplexListNode* pNode = pHead;
    ComplexListNode* pClonedHead = NULL;
    ComplexListNode* pClonedNode = NULL;
 
    if(pNode != NULL)
    {
        pClonedHead = pClonedNode = pNode->m_pNext;
        pNode->m_pNext = pClonedNode->m_pNext;
        pNode = pNode->m_pNext;
    }
 
    while(pNode != NULL)
    {
        pClonedNode->m_pNext = pNode->m_pNext;
        pClonedNode = pClonedNode->m_pNext;
 
        pNode->m_pNext = pClonedNode->m_pNext;
        pNode = pNode->m_pNext;
    }
 
    return pClonedHead;
}

// ==================== Test Code ====================
ComplexListNode* CreateNode(int nValue)
{
    ComplexListNode* pNode = new ComplexListNode();
    
    pNode->m_nValue = nValue;
    pNode->m_pNext = NULL;
    pNode->m_pSibling = NULL;

    return pNode;
}

void BuildNodes(ComplexListNode* pNode, ComplexListNode* pNext, ComplexListNode* pSibling)
{
    if(pNode != NULL)
    {
        pNode->m_pNext = pNext;
        pNode->m_pSibling = pSibling;
    }
}

void PrintList(ComplexListNode* pHead)
{
    ComplexListNode* pNode = pHead;
    while(pNode != NULL)
    {
        printf("The value of this node is: %d.\n", pNode->m_nValue);

        if(pNode->m_pSibling != NULL)
            printf("The value of its sibling is: %d.\n", pNode->m_pSibling->m_nValue);
        else
            printf("This node does not have a sibling.\n");

        printf("\n");

        pNode = pNode->m_pNext;
    }
}

void Test(char* testName, ComplexListNode* pHead)
{
    if(testName != NULL)
        printf("%s begins:\n", testName);

    printf("The original list is:\n");
    PrintList(pHead);

    ComplexListNode* pClonedHead = Clone(pHead);

    printf("The cloned list is:\n");
    PrintList(pClonedHead);
}

//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//  |       |      /|\             /|\
//  --------+--------               |
//          -------------------------
void Test1()
{
    ComplexListNode* pNode1 = CreateNode(1);
    ComplexListNode* pNode2 = CreateNode(2);
    ComplexListNode* pNode3 = CreateNode(3);
    ComplexListNode* pNode4 = CreateNode(4);
    ComplexListNode* pNode5 = CreateNode(5);

    BuildNodes(pNode1, pNode2, pNode3);
    BuildNodes(pNode2, pNode3, pNode5);
    BuildNodes(pNode3, pNode4, NULL);
    BuildNodes(pNode4, pNode5, pNode2);

    Test("Test1", pNode1);
}

// m_pSibling points back to its owner node
//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//         |       | /|\           /|\
//         |       | --             |
//         |------------------------|
void Test2()
{
    ComplexListNode* pNode1 = CreateNode(1);
    ComplexListNode* pNode2 = CreateNode(2);
    ComplexListNode* pNode3 = CreateNode(3);
    ComplexListNode* pNode4 = CreateNode(4);
    ComplexListNode* pNode5 = CreateNode(5);

    BuildNodes(pNode1, pNode2, NULL);
    BuildNodes(pNode2, pNode3, pNode5);
    BuildNodes(pNode3, pNode4, pNode3);
    BuildNodes(pNode4, pNode5, pNode2);

    Test("Test2", pNode1);
}

// m_pSibling pointers form a loop
//          -----------------
//         \|/              |
//  1-------2-------3-------4-------5
//          |              /|\
//          |               |
//          |---------------|
void Test3()
{
    ComplexListNode* pNode1 = CreateNode(1);
    ComplexListNode* pNode2 = CreateNode(2);
    ComplexListNode* pNode3 = CreateNode(3);
    ComplexListNode* pNode4 = CreateNode(4);
    ComplexListNode* pNode5 = CreateNode(5);

    BuildNodes(pNode1, pNode2, NULL);
    BuildNodes(pNode2, pNode3, pNode4);
    BuildNodes(pNode3, pNode4, NULL);
    BuildNodes(pNode4, pNode5, pNode2);

    Test("Test3", pNode1);
}

// only one node
void Test4()
{
    ComplexListNode* pNode1 = CreateNode(1);
    BuildNodes(pNode1, NULL, pNode1);

    Test("Test4", pNode1);
}

// empty list
void Test5()
{
    Test("Test5", NULL);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

    return 0;
}