JZ-C-13

剑指offer第十三题：在O(1)时间内删除链表结点

  1 //============================================================================
  2 // Name        : JZ-C-13.cpp
  3 // Author      : Laughing_Lz
  4 // Version     :
  5 // Copyright   : All Right Reserved
  6 // Description : 在O(1)时间内删除链表结点
  7 //============================================================================
  8
  9 #include <iostream>
 10 #include "List.h"
 11 using namespace std;
 12
 13 /*typedef struct ListNode {
 14  int value;
 15  ListNode* next;
 16  } NODE;*/
 17
 18 void DeleteNode(ListNode** HeadNode, ListNode* ToBeDeleted) {
 19     if (!HeadNode || !ToBeDeleted) {
 20         return;
 21     }
 22     if (ToBeDeleted->m_pNext != NULL) { // 要删除的结点不是尾结点
 23         ListNode* p = ToBeDeleted->m_pNext;
 24         ToBeDeleted->m_nValue = p->m_nValue;
 25         ToBeDeleted->m_pNext = p->m_pNext;
 26         delete p;
 27         p = NULL;
 28     } else if (*HeadNode == ToBeDeleted) { // 链表只有一个结点，删除头结点（也是尾结点）
 29         delete ToBeDeleted;
 30         ToBeDeleted = NULL;
 31         *HeadNode = NULL;
 32     } else { // 链表中有多个结点，删除尾结点
 33         ListNode* p = *HeadNode;
 34         while (p->m_pNext != ToBeDeleted) {
 35             p = p->m_pNext;
 36         }
 37         p->m_pNext = NULL;
 38         delete ToBeDeleted;
 39         ToBeDeleted = NULL;
 40     }
 41
 42 }
 43 // ====================测试代码====================
 44 void Test(ListNode* pListHead, ListNode* pNode) {
 45 //    printf("The original list is: \n");
 46     cout << "The original list is:" << endl;
 47     PrintList(pListHead);
 48
 49 //    printf("The node to be deleted is: \n");
 50     cout << "The node to be deleted is:" << endl;
 51     PrintListNode(pNode);
 52
 53     DeleteNode(&pListHead, pNode);
 54 //    printf("The result list is: \n");
 55     cout << "The result list is:" << endl;
 56     PrintList(pListHead);
 57 }
 58
 59 // 链表中有多个结点，删除中间的结点
 60 void Test1() {
 61     ListNode* pNode1 = CreateListNode(1);
 62     ListNode* pNode2 = CreateListNode(2);
 63     ListNode* pNode3 = CreateListNode(3);
 64     ListNode* pNode4 = CreateListNode(4);
 65     ListNode* pNode5 = CreateListNode(5);
 66
 67     ConnectListNodes(pNode1, pNode2);
 68     ConnectListNodes(pNode2, pNode3);
 69     ConnectListNodes(pNode3, pNode4);
 70     ConnectListNodes(pNode4, pNode5);
 71
 72     Test(pNode1, pNode3);
 73
 74     DestroyList(pNode1);
 75 }
 76
 77 // 链表中有多个结点，删除尾结点
 78 void Test2() {
 79     ListNode* pNode1 = CreateListNode(1);
 80     ListNode* pNode2 = CreateListNode(2);
 81     ListNode* pNode3 = CreateListNode(3);
 82     ListNode* pNode4 = CreateListNode(4);
 83     ListNode* pNode5 = CreateListNode(5);
 84
 85     ConnectListNodes(pNode1, pNode2);
 86     ConnectListNodes(pNode2, pNode3);
 87     ConnectListNodes(pNode3, pNode4);
 88     ConnectListNodes(pNode4, pNode5);
 89
 90     Test(pNode1, pNode5);
 91
 92     DestroyList(pNode1);
 93 }
 94
 95 // 链表中有多个结点，删除头结点
 96 void Test3() {
 97     ListNode* pNode1 = CreateListNode(1);
 98     ListNode* pNode2 = CreateListNode(2);
 99     ListNode* pNode3 = CreateListNode(3);
100     ListNode* pNode4 = CreateListNode(4);
101     ListNode* pNode5 = CreateListNode(5);
102
103     ConnectListNodes(pNode1, pNode2);
104     ConnectListNodes(pNode2, pNode3);
105     ConnectListNodes(pNode3, pNode4);
106     ConnectListNodes(pNode4, pNode5);
107
108     Test(pNode1, pNode1);
109
110     DestroyList(pNode1);
111 }
112
113 // 链表中只有一个结点，删除头结点
114 void Test4() {
115     ListNode* pNode1 = CreateListNode(1);
116
117     Test(pNode1, pNode1);
118 }
119
120 // 链表为空
121 void Test5() {
122     Test(NULL, NULL);
123 }
124
125 int main(int argc, char** argv) {
126     Test1();
127     Test2();
128     Test3();
129     Test4();
130     Test5();
131
132     return 0;
133 }