九度OJ——1201二叉排序树

#include <iostream>
using namespace std;

class BinarySearchTree{
    private:
        int data;
        BinarySearchTree* lchild;
        BinarySearchTree* rchild;
    public:     
        //插入函数
        BinarySearchTree* Insert(BinarySearchTree* bst,int data){
            if(!bst){
                bst = new BinarySearchTree;
                bst->data = data;
                bst->lchild = bst->rchild = NULL;
            }else if(data > bst->data){
                bst->rchild = this->Insert(bst->rchild,data);
            }else if(data < bst->data){
                bst->lchild = this->Insert(bst->lchild,data);
            }
            return bst;
        }

        //前序遍历
        void PreorderTraversal(BinarySearchTree* bst){
            if(!bst){
                return;
            }
            cout<<bst->data<<" ";
            bst->PreorderTraversal(bst->lchild);
            bst->PreorderTraversal(bst->rchild);
        }

        //中序遍历
        void InorderTraversal(BinarySearchTree* bst){
            if(!bst){
                return;
            }
            bst->InorderTraversal(bst->lchild);
            cout<<bst->data<<" ";
            bst->InorderTraversal(bst->rchild);
        }

        //中序遍历
        void PostorderTraversal(BinarySearchTree* bst){
            if(!bst){
                return;
            }
            bst->PostorderTraversal(bst->lchild);
            bst->PostorderTraversal(bst->rchild);
            cout<<bst->data<<" ";
        }
};

int data,N;
BinarySearchTree* bst;

int main()
{
    while(cin>>N){
        bst = NULL; 
        for(int i = 0 ; i < N ; i++){
            cin>>data;
            bst = bst->Insert(bst,data);
        }
        bst->PreorderTraversal(bst);
        cout<<endl;
        bst->InorderTraversal(bst);
        cout<<endl;
        bst->PostorderTraversal(bst);
        cout<<endl;
    }

    return 0;
}