玩轉二叉樹

下附程式碼：

#include <bits/stdc++.h>

using namespace std;
struct node{
    int data;
    node *left_child, *right_child;
};
int a[110], b[110], k = 1;
bool vis[110];
vector<node*> ans;
node* build_tree(int l, int r){
    if(l > r) return NULL;
    node* root;
    root = NULL;
    for(int
 
 i = l;i <= r; ++ i){
        if(a[i] == b[k]){
            root = new node;
            root->data = b[k++];
            root->right_child = build_tree(l, i - 1);
            root->left_child = build_tree(i + 1, r);
            break;
        }
    }
    return root;
}
void build(node* root){
    queue
 
<node*> q;
    q.push(root);
    while(q.size()){
        node* tmp = q.front();
        q.pop();
        ans.push_back(tmp);
        if(tmp->left_child) q.push(tmp->left_child);
        if(tmp->right_child) q.push(tmp->right_child);
    }
}
int n;
int main()
{
    cin >> n;
    
 
for(int i = 1;i <= n; ++ i)
        cin >> a[i];
    for(int i = 1;i <= n; ++ i)
        cin >> b[i];
    node* root = NULL;
    root = build_tree(1, n);
    build(root);
//    cout << ans.size() << endl;                                                            
    
    for(int i = 0;i < ans.size();++ i){
        if(i == ans.size() - 1)
         cout << ans[i]->data;
        else cout << ans[i]->data << " ";
    }    
}