编程算法 - 数组构造二叉树并打印

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数组构造二叉树并打印

本文地址: http://blog.csdn.net/caroline_wendy

数组:

构造二叉树, 需要使用两个队列(queue), 保存子节点和父节点, 并进行交换;

打印二叉树, 需要使用两个队列(queue), 依次打印父节点和子节点, 并进行交换;

二叉树的数据结构:

struct BinaryTreeNode {int m_nValue;BinaryTreeNode* m_pParent;BinaryTreeNode* m_pLeft;BinaryTreeNode* m_pRight;};

代码:

/* * main.cpp * *  Created on: 2014.6.12 *      Author: Spike *//*eclipse cdt, gcc 4.8.1*/#include <iostream>#include <stack>#include <queue>using namespace std;struct BinaryTreeNode {int m_nValue;BinaryTreeNode* m_pParent;BinaryTreeNode* m_pLeft;BinaryTreeNode* m_pRight;};void printTree (BinaryTreeNode* tree){BinaryTreeNode* node = tree;std::queue<BinaryTreeNode*> temp1;std::queue<BinaryTreeNode*> temp2;temp1.push(node);while (!temp1.empty()){node = temp1.front();if (node->m_pLeft != NULL) {temp2.push(node->m_pLeft);}if (node->m_pRight != NULL) {temp2.push(node->m_pRight);}temp1.pop();std::cout << node->m_nValue  << " ";if (temp1.empty()){std::cout << std::endl;temp1 = temp2;std::queue<BinaryTreeNode*> empty;std::swap(temp2, empty);}}}BinaryTreeNode* buildTree (const std::vector<int>& L){if (L.empty()) return nullptr;std::queue<BinaryTreeNode*> parentQueue;std::queue<BinaryTreeNode*> childQueue;BinaryTreeNode* root = new BinaryTreeNode();root->m_nValue = L[0];parentQueue.push(root);std::size_t times = 1;while (times < L.size()){BinaryTreeNode* parent = parentQueue.front();parentQueue.pop();BinaryTreeNode* lchild = new BinaryTreeNode();lchild->m_nValue = L[times];lchild->m_pLeft = nullptr;lchild->m_pRight = nullptr;++times;parent->m_pLeft = lchild;lchild->m_pParent = parent;childQueue.push(lchild);if (times == L.size()) break;BinaryTreeNode* rchild = new BinaryTreeNode();rchild->m_nValue = L[times];rchild->m_pLeft = nullptr;rchild->m_pRight = nullptr;++times;parent->m_pRight = rchild;rchild->m_pParent = parent;childQueue.push(rchild);if (parentQueue.empty()) {parentQueue = childQueue;std::queue<BinaryTreeNode*> empty;std::swap(childQueue, empty);}}return root;}int main (void){std::vector<int> L = {49, 38, 65, 97, 76, 13, 27, 49};BinaryTreeNode* tree = buildTree(L);printTree(tree);return 0;}

输出:

49 38 65 97 76 13 27 49

不包含父节点的树:

/* * main.cpp * *  Created on: 2014.6.12 *      Author: Spike *//*eclipse cdt, gcc 4.8.1*/#include <iostream>#include <stack>#include <queue>using namespace std;struct BinaryTreeNode {int m_nValue;BinaryTreeNode* m_pLeft;BinaryTreeNode* m_pRight;};void printTree (BinaryTreeNode* tree){BinaryTreeNode* node = tree;std::queue<BinaryTreeNode*> temp1;std::queue<BinaryTreeNode*> temp2;temp1.push(node);while (!temp1.empty()){node = temp1.front();if (node->m_pLeft != NULL) {temp2.push(node->m_pLeft);}if (node->m_pRight != NULL) {temp2.push(node->m_pRight);}temp1.pop();std::cout << node->m_nValue  << " ";if (temp1.empty()){std::cout << std::endl;temp1 = temp2;std::queue<BinaryTreeNode*> empty;std::swap(temp2, empty);}}}BinaryTreeNode* buildTree (const std::vector<int>& L){if (L.empty()) return nullptr;std::queue<BinaryTreeNode*> parentQueue;std::queue<BinaryTreeNode*> childQueue;BinaryTreeNode* root = new BinaryTreeNode();root->m_nValue = L[0];parentQueue.push(root);std::size_t times = 1;while (times < L.size()){BinaryTreeNode* parent = parentQueue.front();parentQueue.pop();BinaryTreeNode* lchild = new BinaryTreeNode();lchild->m_nValue = L[times];lchild->m_pLeft = nullptr;lchild->m_pRight = nullptr;++times;parent->m_pLeft = lchild;childQueue.push(lchild);if (times == L.size()) break;BinaryTreeNode* rchild = new BinaryTreeNode();rchild->m_nValue = L[times];rchild->m_pLeft = nullptr;rchild->m_pRight = nullptr;++times;parent->m_pRight = rchild;childQueue.push(rchild);if (parentQueue.empty()) {parentQueue = childQueue;std::queue<BinaryTreeNode*> empty;std::swap(childQueue, empty);}}return root;}int main (void){std::vector<int> L = {49, 38, 65, 97, 76, 13, 27, 49};BinaryTreeNode* tree = buildTree(L);printTree(tree);return 0;}

输出:

49 38 65 97 76 13 27 49

5 0