剑指offer——面试题18:删除链表的节点

 #include"List.h"

 void DeleteNode(ListNode** pHead,ListNode* pToBeDeleted)
 {
     if(*pHead==nullptr || pToBeDeleted==nullptr)
         return;
     if(pToBeDeleted->m_pNext!=nullptr)
     {
         ListNode* pNext=pToBeDeleted->m_pNext;
         pToBeDeleted->m_pNext=pNext->m_pNext;
         pToBeDeleted->m_Value=pNext->m_Value;
         delete pNext;
         pNext=nullptr;
     }
     else if(pToBeDeleted==*pHead)
     {
         delete pToBeDeleted;
         pToBeDeleted=nullptr;
         *pHead=nullptr;
     }
     else
     {
         ListNode* pNode=*pHead;
         while(pNode->m_pNext!=pToBeDeleted)
             pNode=pNode->m_pNext;
         pNode->m_pNext=nullptr;
         delete pToBeDeleted;
         pToBeDeleted=nullptr;
     }
 }
 void Test(ListNode* pListHead, ListNode* pNode)
 {
     printf("The original list is: \n");
     PrintList(pListHead);

     printf("The node to be deleted is: \n");
     PrintListNode(pNode);

     DeleteNode(&pListHead, pNode);

     printf("The result list is: \n");
     PrintList(pListHead);
 }

 // 链表中有多个结点，删除中间的结点
 void Test1()
 {
     ListNode* pNode1 = CreateListNode();
     ListNode* pNode2 = CreateListNode();
     ListNode* pNode3 = CreateListNode();
     ListNode* pNode4 = CreateListNode();
     ListNode* pNode5 = CreateListNode();

     ConnectListNodes(pNode1, pNode2);
     ConnectListNodes(pNode2, pNode3);
     ConnectListNodes(pNode3, pNode4);
     ConnectListNodes(pNode4, pNode5);

     Test(pNode1, pNode3);

     DestroyList(pNode1);
 }

 // 链表中有多个结点，删除尾结点
 void Test2()
 {
     ListNode* pNode1 = CreateListNode();
     ListNode* pNode2 = CreateListNode();
     ListNode* pNode3 = CreateListNode();
     ListNode* pNode4 = CreateListNode();
     ListNode* pNode5 = CreateListNode();

     ConnectListNodes(pNode1, pNode2);
     ConnectListNodes(pNode2, pNode3);
     ConnectListNodes(pNode3, pNode4);
     ConnectListNodes(pNode4, pNode5);

     Test(pNode1, pNode5);

     DestroyList(pNode1);
 }

 // 链表中有多个结点，删除头结点
 void Test3()
 {
     ListNode* pNode1 = CreateListNode();
     ListNode* pNode2 = CreateListNode();
     ListNode* pNode3 = CreateListNode();
     ListNode* pNode4 = CreateListNode();
     ListNode* pNode5 = CreateListNode();

     ConnectListNodes(pNode1, pNode2);
     ConnectListNodes(pNode2, pNode3);
     ConnectListNodes(pNode3, pNode4);
     ConnectListNodes(pNode4, pNode5);

     Test(pNode1, pNode1);

     DestroyList(pNode1);
 }

 // 链表中只有一个结点，删除头结点
 void Test4()
 {
     ListNode* pNode1 = CreateListNode();

     Test(pNode1, pNode1);
 }

 // 链表为空
 void Test5()
 {
     Test(nullptr, nullptr);
 }

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

     return ;
 }