题解 | #二叉树遍历#

#include <string>
#include <iostream>
using namespace std;

struct TreeNode
{
    char data;
    TreeNode *left;
    TreeNode *right;
    TreeNode(char c):data(c),left(NULL),right(NULL){}
};

TreeNode* build(const string & str1, const string  &str2);
void postorder(TreeNode * r);
int main(int nums ,char ** args)
{
    ios::sync_with_stdio(false);
    string str1,str2;
    while(cin>>str1>>str2)
    {
        TreeNode*r=build(str1,str2);
        postorder(r);
        cout<<endl;

    }

    return 0;
}
TreeNode* build(const string & str1, const string  &str2)
{
    if(str1.size()==0)
        {return NULL;}
    int pos=str2.find(str1[0]);
    TreeNode* r=new TreeNode(str1[0]);
    r->left=build(str1.substr(1,pos),str2.substr(0,pos));
    r->right=build(str1.substr(1+pos),str2.substr(1+pos));
    return r;
}
void postorder(TreeNode * r)
{
    if(r==NULL) return;
    postorder(r->left);
    postorder(r->right);
    cout<<r->data;
}