《數據結構與算法實戰-周強-4.1》——統計無後代的人數

實現代碼：

// 二叉樹的先序中序後序實現

#include <iostream>
using namespace std;

template<class Elem>
struct BinNode{
    Elem data;
    BinNode<Elem>* left;
    BinNode<Elem>* right;
    BinNode(Elem x){
        data=x;
        left=right=NULL;
    }
};

template<class Elem>
class BinTree{
protected:
    BinNode<Elem>* root;
    void rpreprint(BinNode<Elem>* r){   // 對於傳指針，一定不要掉以輕心，要首先看一下指針是不是空指針
        if(r==NULL) return;
        cout<<r->data<<" ";
        rpreprint(r->left);
        rpreprint(r->right);
    }
    void rinprint(BinNode<Elem>* r){
        if(r==NULL) return;
        rinprint(r->left);
        cout<<r->data<<" ";
        rinprint(r->right);
    }
    void rpostprint(BinNode<Elem>* r){
        if(r==NULL) return;
        rinprint(r->left);
        rinprint(r->right);
        cout<<r->data<<" ";
    }
    int cntLeaves(BinNode<Elem>* r){
        if(r==NULL) return 0;
        if(r->left==NULL && r->right==NULL) return 1;
        return cntLeaves(r->left)+cntLeaves(r->right);
    }
    BinNode<Elem>* rfindX(Elem x,BinNode<Elem>* r){
        if(!r)   return NULL;
        if(r->data==x)   return r;
        BinNode<Elem>* found;
        found=rfindX(x,r->left);
        return found?found:rfindX(x,r->right);
    }
    void rprint(BinNode<Elem>* r,int depth){
        for(int i=0;i<depth;i++)    cout<<"  ";
        if(!r){
            cout<<"[/]"<<endl;
        }
        else{
            cout<<r->data<<endl;
        rprint(r->left,depth+1);
        rprint(r->right,depth+1);
        }
    }

public:
    BinTree()   {root=NULL;}
    BinTree(Elem r){
        root=new BinNode<Elem>(r);
    }
    ~BinTree(){ };
    void preprint(){
        rpreprint(root);
        cout<<endl;
    }
    void inprint(){
        rinprint(root);
    }
    void postprint(){
        rpostprint(root);
    }
    void print(){
        rprint(root,0);
    }
    BinNode<Elem>* findX(Elem x){
        return rfindX(x,root);
    }
    bool insert(Elem p,int LorR,Elem x){
        BinNode<Elem>* found;
        found=findX(p);
        if(!found)  return false;
        if(LorR==0){
            if(found->left) return false;
            found->left=new BinNode<Elem>(x);
        }
        else{
            if(found->right)    return false;
            found->right=new BinNode<Elem>(x);
        }
        return true;
    }
    int cnt(){
        return cntLeaves(root);
    }
};

int main(){
    string name;
    cin>>name;
    BinTree<string> bt(name);
    cin>>name;
    while(name!="-"){
        string  lc,rc;
        cin>>lc>>rc;
        if(lc!="-") bt.insert(name,0,lc);
        if(rc!="-") bt.insert(name,1,rc);
        cin>>name;
    }
    cout<<"葉子數目："<<bt.cnt()<<endl;
    return 0;
}
/*
Ann
Ann Bill Chris
Bill Daisy Ellen
Chric - Flin
Dasiy - -
Ellen Grace Henry
Flin - -
Grace - -
Henry - -
-
*/