已知先序中序求后序

最新推荐文章于 2022-05-22 14:33:31 发布

原创最新推荐文章于 2022-05-22 14:33:31 发布 · 546 阅读

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#ACM #C++ #树

#include<iostream>

#include<string>
using namespace std;
class Node {
public:
    int data;
    Node *lchild, *rchild;
    Node(int _data) {
        data = _data;
        lchild = NULL;
        rchild = NULL;
    }
    ~Node() {
        if (lchild != NULL) {
            delete lchild;
        }
        if (rchild != NULL) {
            delete rchild;
        }
    }
    void postorder() {
        if (lchild != NULL) {
            lchild->postorder();
        }
        if (rchild != NULL) {
            rchild->postorder();
        }
        cout << data << " ";
    }
    Node* build(const string&pre_str,const string&in_str,int len){
        Node *p=new Node(pre_str[0]-'0');
        int pos=in_str.find(pre_str[0]);
        if(pos>0)
        {
           p->lchild=build(pre_str.substr(1,pos),in_str.substr(0,pos),pos);   
        }
        if(len-pos-1>0)
        {
         p->rchild=build(pre_str.substr(pos+1),in_str.substr(pos+1),len-pos-1);   
        }
        return p;
    }
};
class BinaryTree {
private:
    Node *root;
public:
    BinaryTree() {
        root = NULL;
    }
    ~BinaryTree() {
        if (root != NULL) {
            delete root;
        }
    }
    BinaryTree(const string& pre_str,const string & in_str,int len)
    {
        root=root->build(pre_str,in_str,len);   
    }
    void postorder() {
        root->postorder();
    }
};
int main() {
    string pre_str = "136945827";
    string in_str = "963548127";
    BinaryTree binarytree(pre_str,in_str,in_str.length());
    binarytree.postorder();
    cout<<endl;
    return 0;
}