// 面试题27:二叉树的镜像 // 题目:请完成一个函数,输入一个二叉树,该函数输出它的镜像。 #include <iostream> #include "BinaryTree.h" #include <stack> void MirrorRecursively(BinaryTreeNode *pNode)//递归算法(自下而上) { if ((pNode == nullptr) || (pNode->m_pLeft == nullptr && pNode->m_pRight == nullptr))//鲁棒性 return; BinaryTreeNode *pTemp = pNode->m_pLeft;//交换 pNode->m_pLeft = pNode->m_pRight; pNode->m_pRight = pTemp; if (pNode->m_pLeft)//遍历 MirrorRecursively(pNode->m_pLeft); if (pNode->m_pRight) MirrorRecursively(pNode->m_pRight); } void MirrorIteratively(BinaryTreeNode* pRoot)//迭代算法(自上而下) { if (pRoot == nullptr) return; std::stack<BinaryTreeNode*> stackTreeNode;//建立一个栈 stackTreeNode.push(pRoot);//压入根节点 while (stackTreeNode.size() > 0)//当栈内有元素时 { BinaryTreeNode *pNode = stackTreeNode.top();//取出栈顶元素 stackTreeNode.pop(); BinaryTreeNode *pTemp = pNode->m_pLeft;//交换该元素(即节点)的孩子 pNode->m_pLeft = pNode->m_pRight; pNode->m_pRight = pTemp; if (pNode->m_pLeft)//如果节点孩子存在,把孩子压入堆栈 stackTreeNode.push(pNode->m_pLeft); if (pNode->m_pRight) stackTreeNode.push(pNode->m_pRight); } } // ====================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(8); BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6); BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10); BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5); BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7); BinaryTreeNode* pNode9 = CreateBinaryTreeNode(9); BinaryTreeNode* pNode11 = CreateBinaryTreeNode(11); 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 // 4 void Test2() { printf("=====Test2 starts:=====\n"); BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8); BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7); BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6); BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5); BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4); 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(8); BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7); BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6); BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5); BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4); 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(8); 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(); system("pause"); return 0; }
原文地址:https://www.cnblogs.com/CJT-blog/p/10490813.html
时间: 2024-11-05 23:26:59