C++ 统计二叉树中所有结子数、叶子节点数

计算所有结点数核心代码：

int count_BT(BinaryTreeNode *myBT)//递归求解二叉树所有结点数
{
	if(myBT == nullptr)
		return 0;
	int count = 0;
	count = 1+ count_BT(myBT->m_pLeft) + count_BT(myBT->m_pRight);
	return count;
} 

计算叶子节点数核心代码：

void count_leaf(BinaryTreeNode *myBT,int &count)//前序遍历计算二叉树叶子结点数
{
	if(myBT == nullptr)
		return ;
		
	if(myBT->m_pLeft == nullptr && myBT->m_pRight == nullptr)
		count++;

	count_leaf(myBT->m_pLeft,count);
	count_leaf(myBT->m_pRight,count);		 
} 

int count_leaf(BinaryTreeNode *myBT)//分治法计算二叉树叶子结点数
{
	int count; 
	if(myBT == nullptr)
		count = 0;
	else if(myBT->m_pLeft == nullptr && myBT->m_pRight == nullptr)
		count = 1;
	else//注意这里要是else条件下才能执行,否则会造成死循环 
		count = count_leaf(myBT->m_pLeft) + count_leaf(myBT->m_pRight);	
	
	return count;	 
}

全部代码如下：

#include<iostream>
#include<queue>
using namespace std;
 
struct BinaryTreeNode{
	int value;
	BinaryTreeNode *m_pLeft;
	BinaryTreeNode *m_pRight;
};
 
void addBTNode(BinaryTreeNode **myBT,int val);//添加节点，满足每个父亲节点大于左边的，小于右边的 
void levels_showBT(BinaryTreeNode *myBT);//层次遍历,利用队列实现

int count_BT(BinaryTreeNode *myBT);//二叉树所有结点数
void count_leaf(BinaryTreeNode *myBT,int &count);//前序遍历计算二叉树叶子结点数
int count_leaf(BinaryTreeNode *myBT);//分治法计算二叉树叶子结点数
 
int main(){
	
	BinaryTreeNode *myBT = nullptr;
	
	addBTNode(&myBT,10);
	addBTNode(&myBT,2);
	addBTNode(&myBT,3);
	addBTNode(&myBT,15);
	addBTNode(&myBT,18);
	addBTNode(&myBT,1);
	addBTNode(&myBT,16);
	
	levels_showBT(myBT);
	
	cout<<"二叉树的结点数为:"<<count_BT(myBT)<<endl;
	
	int count = 0;
	count_leaf(myBT,count);
	cout<<"前序遍历计算二叉树的结子点数为:"<<count<<endl;
	
	cout<<"分治法计算二叉树的结子点数为:"<<count_leaf(myBT)<<endl;
	
	return 0;
}

int count_BT(BinaryTreeNode *myBT)//二叉树所有结点数
{
	if(myBT == nullptr)
		return 0;
	int count = 0;
	count = 1+ count_BT(myBT->m_pLeft) + count_BT(myBT->m_pRight);
	return count;
}

void count_leaf(BinaryTreeNode *myBT,int &count)//前序遍历计算二叉树叶子结点数
{
	if(myBT == nullptr)
		return ;
		
	if(myBT->m_pLeft == nullptr && myBT->m_pRight == nullptr)
		count++;

	count_leaf(myBT->m_pLeft,count);
	count_leaf(myBT->m_pRight,count);		 
} 

int count_leaf(BinaryTreeNode *myBT)//分治法计算二叉树叶子结点数
{
	int count; 
	if(myBT == nullptr)
		count = 0;
	else if(myBT->m_pLeft == nullptr && myBT->m_pRight == nullptr)
		count = 1;
	else//注意这里要是else条件下才能执行,否则会造成死循环 
		count = count_leaf(myBT->m_pLeft) + count_leaf(myBT->m_pRight);	
	
	return count;	 
}
 
 
void addBTNode(BinaryTreeNode **myBT,int val){
	if(*myBT == nullptr){
		*myBT = new BinaryTreeNode();
		(*myBT)->value = val;
		(*myBT)->m_pLeft = nullptr;
		(*myBT)->m_pRight = nullptr;
		return;	
	}
		
	if(val == (*myBT)->value){
		return;
	}
	else if(val < (*myBT)->value){
		addBTNode(&(*myBT)->m_pLeft,val);
	}
	else{
		addBTNode(&(*myBT)->m_pRight,val);
	}			
}
 
void levels_showBT(BinaryTreeNode *myBT){//层次遍历,利用队列实现 
	if(myBT == nullptr )
		return;
	
	queue<BinaryTreeNode *> que;//构造一个树结点指针的队列 
	que.push(myBT);
 
	while(!que.empty()){
		
		if( (que.front())->m_pLeft != nullptr)
			que.push( (que.front())->m_pLeft );
			
		if( (que.front())->m_pRight != nullptr)
			que.push( (que.front())->m_pRight );
		
		cout<<(que.front())->value<<" ";
		que.pop();
	}
	cout<<endl;
		
} 

运行代码如下: