题目：https://www.nowcoder.com/practice/4b91205483694f449f94c179883c1fef?tpId=40&tqId=21342&tPage=1&rp=1&ru=/ta/kaoyan&qru=/ta/kaoyan/question-ranking

主要是建树的代码还不太熟悉，说明自己这方面还有点薄弱

代码

  1. #include <cstdio>
  2. #include <string>
  3. #include <iostream>
  4. using namespace std;
  5. string input;
  6. int pos;
  7. struct Node{
  8.     char name;
  9.     Node * lchild;
  10.     Node * rchild;
  11. }node;
  13. Node* create(){
  14.     char c = input[pos++];
  15.     if(c == '#'){
  16.         return NULL;
  17.     }
  18.     Node *root = new Node;
  19.     root->name = c;
  20.     root->lchild = create();
  21.     root->rchild = create();
  22.     return root;
  23. }
  25. void PreOrder(Node *root){
  26.     if(root == NULL) return;
  27.     PreOrder(root->lchild);
  28.     printf("%c ", root->name);
  29.     PreOrder(root->rchild);
  30.     return;
  31. }
  33. int main(){
  34.     while(getline(cin, input), input != ""){
  35.         pos = 0;
  36.         Node *root = create();
  37.         PreOrder(root);
  38.         printf("\n");
  39.     }
  40. }