关于树的常见操作-C++面试

 #include <iostream>
 using namespace std;

 //树的存储结构与设计
 struct BitNode
 {
     int data;
     BitNode* leftChild;
     BitNode* rightChild;
     BitNode()
     {
         leftChild = NULL;
         rightChild = NULL;
     }
     BitNode(int x) :data(x), leftChild(NULL), rightChild(NULL)
     {

     }
 };
 //树的先序遍历
 void PreOrder(BitNode* T)
 {
     if (T == NULL)
     {
         return;
     }
     cout << T->data;
     PreOrder(T->leftChild);
     PreOrder(T->rightChild);
     return;

 }
 //树的中序遍历
 void InOrder(BitNode* T)
 {
     if (T == NULL)
     {
         return;
     }
     InOrder(T->leftChild);
     cout << T->data;
     InOrder(T->rightChild);
     return;
 }
 //树的后序遍历
 void PostOrder(BitNode* T)
 {
     if (T == NULL)
     {
         return;
     }
     PostOrder(T->leftChild);
     PostOrder(T->rightChild);
     cout << T->data;
 }
 //求树的叶子结点个数
 int sum = ;
 int CountLeafNum(BitNode* T)
 {

     if (T == NULL)
     {
         return ;
     }
     if (T->leftChild == NULL && T->rightChild == NULL)
     {
         sum++;
     }
     CountLeafNum(T->leftChild);
     CountLeafNum(T->rightChild);
     return sum;
 }
 //求树的叶子结点个数-两个参数
 void CountLeafNum(BitNode* T, int* sum)
 {
     if (T == NULL)
     {
         return;
     }
     if (T->leftChild == NULL && T->rightChild == NULL)
     {
         *sum = *sum + ; //等价于(*sum)++
     }
     CountLeafNum(T->leftChild, sum);
     CountLeafNum(T->rightChild, sum);
 }
 //求树的深度
 int DepthOfTree(BitNode* T)
 {
     int depthLeft = ;
     int depthRight = ;
     int depth = ;
     if (T == NULL)
         return ;
     depthLeft = DepthOfTree(T->leftChild);
     depthRight = DepthOfTree(T->rightChild);
     depth =  + ((depthLeft >depthRight)? depthLeft : depthRight);
     return depth;
 }
 //复制二叉树--用递归的思想，必须先根据返回值，定义新的变量类型用于递归的返回值赋值
 BitNode* Copy(BitNode* T)
 {
     if (T == NULL)
     {
         return NULL;
     }
     //用的前序遍历思想
     BitNode* newTreeLeft = Copy(T->leftChild);
     BitNode* newTreeRight = Copy(T->rightChild);

     //建立一个结点
     BitNode* newNode = new BitNode();
     if (newNode == NULL)
     {
         return NULL;
     }
     newNode->data = T->data;
     newNode->leftChild = newTreeLeft;
     newNode->rightChild = newTreeRight;
     return newNode;
 }
 int main()
 {
     BitNode nodeA();
     BitNode nodeB();
     BitNode nodeC();
     BitNode nodeD();
     BitNode nodeE();
     BitNode nodeF();

     nodeA.leftChild = &nodeB;
     nodeA.rightChild = &nodeC;
     nodeB.leftChild = &nodeD;
     nodeB.rightChild = &nodeE;
     nodeC.leftChild = &nodeF;

     //前序遍历二叉树
     cout << "前序遍历二叉树 " << ":";
     PreOrder(&nodeA);
     cout << endl;
     //中序遍历二叉树
     cout << "中序遍历二叉树 " << ":";
     InOrder(&nodeA);
     cout << endl;
     //后序遍历二叉树
     cout << "后序遍历二叉树 " << ":";
     PostOrder(&nodeA);
     cout << endl;

     //树的结点个数
     int leafCount = CountLeafNum(&nodeA);
     cout << "树的结点个数:" << leafCount << endl;

     //树的深度
     int depth = DepthOfTree(&nodeA);
     cout << "树的深度:" << depth << endl;

     //赋值一棵树
     BitNode* newNode = Copy(&nodeA);
     //后序遍历二叉树
     cout << "后序遍历二叉树 " << ":";
     PostOrder(newNode);
     cout << endl;

     system("pause");
     return ;
 }