数据结构 - 把二元查找树转变成排序的双向链表（C++）

//****************************************************************************************************////  把二元查找树转变成排序的双向链表 - C++ - by Chimomo//// 【思路】: 按照二叉树的中序遍历正好按从小到大地顺序遍历全部节点。在遍历的过程中，更改它的逻辑结构。////****************************************************************************************************#include <iostream>using namespace std;// The binary search tree node.struct BSTreeNode{int m_nValue; // The value of node.BSTreeNode *m_pLeft; // The left child of node.BSTreeNode *m_pRight; // The right child of node.};typedef BSTreeNode DoubleLinkedList;DoubleLinkedList *pHead = NULL;DoubleLinkedList *pDoubleLinkedList = NULL;// Construct binary search tree recursively.void ConstructBSTree(BSTreeNode *& pCurrent, int value) // Use & here since pCurrent will be changed in the function body.{if(pCurrent == NULL){BSTreeNode * pTree = new BSTreeNode();pTree->m_pLeft = NULL;pTree->m_pRight = NULL;pTree->m_nValue = value;pCurrent = pTree;}else{if(value > pCurrent->m_nValue){ConstructBSTree(pCurrent->m_pRight,value);}else if(value < pCurrent->m_nValue){ConstructBSTree(pCurrent->m_pLeft,value);}else{cout<<"Invalid input, there already have the value!"<<endl;}}}// Convert binary search tree node to double linked list node.void ConvertBSTreeNodeToDoubleLinkedListNode(BSTreeNode * pCurrent){pCurrent->m_pLeft = pDoubleLinkedList;if (pDoubleLinkedList == NULL){pHead = pCurrent;}else{pDoubleLinkedList->m_pRight = pCurrent;}pDoubleLinkedList = pCurrent;}// Traverse binary search tree (inorder) to convert binary tree to double linked list.void TraverseBSTreeInorder(BSTreeNode * pCurrent){if(pCurrent == NULL){return;}else{if(pCurrent->m_pLeft != NULL){TraverseBSTreeInorder(pCurrent->m_pLeft);}ConvertBSTreeNodeToDoubleLinkedListNode(pCurrent);if(pCurrent->m_pRight != NULL){TraverseBSTreeInorder(pCurrent->m_pRight);}}}int main(int argc, char* argv[]){int value;BSTreeNode *pBSTree = NULL;cout << "Please input integers, -1 to end: ";cin >> value;while(-1 != value){ConstructBSTree(pBSTree, value);cin >> value;}TraverseBSTreeInorder(pBSTree);while(pHead){cout << pHead->m_nValue << endl;pHead = pHead->m_pRight;}return 0;}// Output:/*Please input integers, -1 to end: 6 7 8 5 4 3 9 2 1 0 10 -1012345678910*/