每天一个小算法（4）----在O(1)时间删除指定结点

O(1)时间内删除结点的思路只能是复制该结点下一个结点的数据，然后删除该结点的下一个结点，来等效删除此结点。

需要注意的地方是删除头结点和尾结点的处理。

 #include <stdio.h>
 #include <time.h>
 #include <stdlib.h>
 typedef struct Node
 {
     int data;
     Node* next;
 }Node, *List;

 List createList(int num) //随机生成数字，构造链表
 {
     List aList = (List)malloc(sizeof(Node));
     aList->next = NULL;
     aList->data = ;
     Node* qT = aList;

      // srand((int)time(0));
      for ( int i=; i< num; ++i)
      {
          Node* pTN = (Node*)malloc(sizeof(Node));
          pTN->data = rand()%;
          pTN->next = NULL;
          qT->next = pTN;
          qT = pTN;
      }
      return aList;
 }

 void printList(List aList)    //打印链表
 {
     if ( aList == NULL || aList->next == NULL )
         return;

     Node* pT = aList->next;
     printf("element of list:\n\t");
     while( pT != NULL )
     {
         printf("%d ", pT->data);
         pT = pT->next;
     }

     printf("\n");
 }

 void deleteList(List aList)    //删除链表
 {}

 //删除结点主算法
 void deleteNode(List aList, Node* pNode)
 {
     if ( aList == NULL || pNode == NULL )
         return;

     if ( aList == pNode )
     {
         printf("refuse to delete head node\n");
         return;
     }

     if ( pNode->next == NULL )
     {
         Node* pT = aList->next;
         while ( pT->next != NULL )
         {
             pT = pT->next;
         }

         delete pNode;
         pT->next == NULL;
     }

     Node* pN = pNode->next;
     pNode->data = pNode->next->data;
     pNode->next = pNode->next->next;

     delete pN;
 }

 int main(int argc, char const *argv[])
 {
      srand((int)time());
     List aList = createList();
     printList(aList);
     deleteNode(aList,aList->next->next);
     printList(aList);
     deleteList(aList);

     return ;
 }