JZ-C-27

剑指offer第二十七题：二叉搜索树和双向链表

  1 //============================================================================
  2 // Name        : JZ-C-27.cpp
  3 // Author      : Laughing_Lz
  4 // Version     :
  5 // Copyright   : All Right Reserved
  6 // Description : 二叉搜索树和双向链表
  7 //============================================================================
  8 
  9 #include <iostream>
 10 #include <stdio.h>
 11 #include "BinaryTree.h"
 12 using namespace std;
 13 void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList);
 14 
 15 BinaryTreeNode* Convert(BinaryTreeNode* pRootOfTree) {
 16     BinaryTreeNode* pLastNodeInList = NULL;
 17     ConvertNode(pRootOfTree, &pLastNodeInList); //遍历二叉搜索树，并转换为双向链表
 18     // pLastNodeInList指向双向链表的尾结点，
 19     // 我们需要返回头结点
 20     BinaryTreeNode *pHeadOfList = pLastNodeInList;
 21     while (pHeadOfList != NULL && pHeadOfList->m_pLeft != NULL) {
 22         pHeadOfList = pHeadOfList->m_pLeft;
 23     }
 24     return pHeadOfList;
 25 }
 26 /**
 27  * 遍历二叉搜索树，并转换为双向链表
 28  */
 29 void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList) {
 30     if (pNode == NULL) {
 31         return;
 32     }
 33     BinaryTreeNode *pCurrent = pNode;    //★
 34     if (pCurrent->m_pLeft != NULL) {
 35         ConvertNode(pCurrent->m_pLeft, pLastNodeInList);
 36     }
 37     /*****★★★★★重点看这里★★★★★******/
 38     pCurrent->m_pLeft = *pLastNodeInList;//前一个结点
 39     if(*pLastNodeInList != NULL){
 40         (*pLastNodeInList)->m_pRight = pCurrent;//后一个结点
 41     }
 42     *pLastNodeInList = pCurrent;//双向链表的最后一个结点，位置向后移动一位
 43 
 44     if (pCurrent->m_pRight != NULL) {
 45         ConvertNode(pCurrent->m_pRight, pLastNodeInList);
 46     }
 47 }
 48 // ====================测试代码====================
 49 void PrintDoubleLinkedList(BinaryTreeNode* pHeadOfList)
 50 {
 51     BinaryTreeNode* pNode = pHeadOfList;
 52 
 53     printf("The nodes from left to right are:\n");
 54     while(pNode != NULL)
 55     {
 56         printf("%d\t", pNode->m_nValue);
 57 
 58         if(pNode->m_pRight == NULL)
 59             break;
 60         pNode = pNode->m_pRight;
 61     }
 62 
 63     printf("\nThe nodes from right to left are:\n");
 64     while(pNode != NULL)
 65     {
 66         printf("%d\t", pNode->m_nValue);
 67 
 68         if(pNode->m_pLeft == NULL)
 69             break;
 70         pNode = pNode->m_pLeft;
 71     }
 72 
 73     printf("\n");
 74 }
 75 
 76 void DestroyList(BinaryTreeNode* pHeadOfList)
 77 {
 78     BinaryTreeNode* pNode = pHeadOfList;
 79     while(pNode != NULL)
 80     {
 81         BinaryTreeNode* pNext = pNode->m_pRight;
 82 
 83         delete pNode;
 84         pNode = pNext;
 85     }
 86 }
 87 
 88 void Test(char* testName, BinaryTreeNode* pRootOfTree)
 89 {
 90     if(testName != NULL)
 91         printf("%s begins:\n", testName);
 92 
 93     PrintTree(pRootOfTree);
 94 
 95     BinaryTreeNode* pHeadOfList = Convert(pRootOfTree);
 96 
 97     PrintDoubleLinkedList(pHeadOfList);
 98 }
 99 
100 //            10
101 //         /      \
102 //        6        14
103 //       /\        /\
104 //      4  8     12  16
105 void Test1()
106 {
107     BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
108     BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
109     BinaryTreeNode* pNode14 = CreateBinaryTreeNode(14);
110     BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
111     BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
112     BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
113     BinaryTreeNode* pNode16 = CreateBinaryTreeNode(16);
114 
115     ConnectTreeNodes(pNode10, pNode6, pNode14);
116     ConnectTreeNodes(pNode6, pNode4, pNode8);
117     ConnectTreeNodes(pNode14, pNode12, pNode16);
118 
119     Test("Test1", pNode10);
120 
121     DestroyList(pNode4);
122 }
123 
124 //               5
125 //              /
126 //             4
127 //            /
128 //           3
129 //          /
130 //         2
131 //        /
132 //       1
133 void Test2()
134 {
135     BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
136     BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
137     BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
138     BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
139     BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
140 
141     ConnectTreeNodes(pNode5, pNode4, NULL);
142     ConnectTreeNodes(pNode4, pNode3, NULL);
143     ConnectTreeNodes(pNode3, pNode2, NULL);
144     ConnectTreeNodes(pNode2, pNode1, NULL);
145 
146     Test("Test2", pNode5);
147 
148     DestroyList(pNode1);
149 }
150 
151 // 1
152 //  \
153 //   2
154 //    \
155 //     3
156 //      \
157 //       4
158 //        \
159 //         5
160 void Test3()
161 {
162     BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
163     BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
164     BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
165     BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
166     BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
167 
168     ConnectTreeNodes(pNode1, NULL, pNode2);
169     ConnectTreeNodes(pNode2, NULL, pNode3);
170     ConnectTreeNodes(pNode3, NULL, pNode4);
171     ConnectTreeNodes(pNode4, NULL, pNode5);
172 
173     Test("Test3", pNode1);
174 
175     DestroyList(pNode1);
176 }
177 
178 // 树中只有1个结点
179 void Test4()
180 {
181     BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
182     Test("Test4", pNode1);
183 
184     DestroyList(pNode1);
185 }
186 
187 // 树中没有结点
188 void Test5()
189 {
190     Test("Test5", NULL);
191 }
192 
193 int main(int argc, char** argv)
194 {
195     Test1();
196     Test2();
197     Test3();
198     Test4();
199     Test5();
200 
201     return 0;
202 }

 

posted @ 2016-06-16 19:52  回看欧洲  阅读(164)  评论(0)  编辑  收藏  举报