剑指offer——面试题27：二叉树的镜像

函数递归

 void MirrorIteratively(BinaryTreeNode* pRoot)
 {
     if(pRoot == nullptr)
         return;

     std::stack<BinaryTreeNode*> stackTreeNode;
     stackTreeNode.push(pRoot);

     while(stackTreeNode.size() > )
     {
         BinaryTreeNode *pNode = stackTreeNode.top();
         stackTreeNode.pop();

         BinaryTreeNode *pTemp = pNode->m_pLeft;
         pNode->m_pLeft = pNode->m_pRight;
         pNode->m_pRight = pTemp;

         if(pNode->m_pLeft)
             stackTreeNode.push(pNode->m_pLeft);

         if(pNode->m_pRight)
             stackTreeNode.push(pNode->m_pRight);
     }
 }

函数循环

 #include"BinaryTree.h"

 // ====================测试代码====================
 // 测试完全二叉树：除了叶子节点，其他节点都有两个子节点
 //            8
 //        6      10
 //       5 7    9  11
 void Test1()
 {
     printf("=====Test1 starts:=====\n");
     BinaryTreeNode* pNode8 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode6 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode10 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode5 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode7 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode9 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode11 = CreateBinaryTreeNode();

     ConnectTreeNodes(pNode8, pNode6, pNode10);
     ConnectTreeNodes(pNode6, pNode5, pNode7);
     ConnectTreeNodes(pNode10, pNode9, pNode11);

     PrintTree(pNode8);

     printf("=====Test1: MirrorRecursively=====\n");
     MirrorRecursively(pNode8);
     PrintTree(pNode8);

     printf("=====Test1: MirrorIteratively=====\n");
     MirrorIteratively(pNode8);
     PrintTree(pNode8);

     DestroyTree(pNode8);
 }

 // 测试二叉树：出叶子结点之外，左右的结点都有且只有一个左子结点
 //            8
 //          7
 //        6
 //      5
 //
 void Test2()
 {
     printf("=====Test2 starts:=====\n");
     BinaryTreeNode* pNode8 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode7 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode6 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode5 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode4 = CreateBinaryTreeNode();

     ConnectTreeNodes(pNode8, pNode7, nullptr);
     ConnectTreeNodes(pNode7, pNode6, nullptr);
     ConnectTreeNodes(pNode6, pNode5, nullptr);
     ConnectTreeNodes(pNode5, pNode4, nullptr);

     PrintTree(pNode8);

     printf("=====Test2: MirrorRecursively=====\n");
     MirrorRecursively(pNode8);
     PrintTree(pNode8);

     printf("=====Test2: MirrorIteratively=====\n");
     MirrorIteratively(pNode8);
     PrintTree(pNode8);

     DestroyTree(pNode8);
 }

 // 测试二叉树：出叶子结点之外，左右的结点都有且只有一个右子结点
 //            8
 //             7
 //              6
 //               5
 //                4
 void Test3()
 {
     printf("=====Test3 starts:=====\n");
     BinaryTreeNode* pNode8 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode7 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode6 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode5 = CreateBinaryTreeNode();
     BinaryTreeNode* pNode4 = CreateBinaryTreeNode();

     ConnectTreeNodes(pNode8, nullptr, pNode7);
     ConnectTreeNodes(pNode7, nullptr, pNode6);
     ConnectTreeNodes(pNode6, nullptr, pNode5);
     ConnectTreeNodes(pNode5, nullptr, pNode4);

     PrintTree(pNode8);

     printf("=====Test3: MirrorRecursively=====\n");
     MirrorRecursively(pNode8);
     PrintTree(pNode8);

     printf("=====Test3: MirrorIteratively=====\n");
     MirrorIteratively(pNode8);
     PrintTree(pNode8);

     DestroyTree(pNode8);
 }

 // 测试空二叉树：根结点为空指针
 void Test4()
 {
     printf("=====Test4 starts:=====\n");
     BinaryTreeNode* pNode = nullptr;

     PrintTree(pNode);

     printf("=====Test4: MirrorRecursively=====\n");
     MirrorRecursively(pNode);
     PrintTree(pNode);

     printf("=====Test4: MirrorIteratively=====\n");
     MirrorIteratively(pNode);
     PrintTree(pNode);
 }

 // 测试只有一个结点的二叉树
 void Test5()
 {
     printf("=====Test5 starts:=====\n");
     BinaryTreeNode* pNode8 = CreateBinaryTreeNode();

     PrintTree(pNode8);

     printf("=====Test4: MirrorRecursively=====\n");
     MirrorRecursively(pNode8);
     PrintTree(pNode8);

     printf("=====Test4: MirrorIteratively=====\n");
     MirrorIteratively(pNode8);
     PrintTree(pNode8);
 }

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

     return ;
 }

测试代码