Doubt regarding input formats- Trees

rachitbansal2500 · June 4, 2020, 8:26pm

Please let me know how to deal with inputs of the form:
10 true 20 true 40 false false true 50 false false true 30 true 60 false false true 73 false false
How to create BT if level order traversal is given

asaurabh_26 · June 5, 2020, 7:12am

for this you have to use recursion

 node* buildTree(){
     int d;
     cin>>d;
     node*nn=new node(d);
     string str;
     cin>>str;  
     if(str=="true")nn->left=buildTree();
     else nn->left=NULL;
     cin>>str;
     if(str=="true")nn->right=buildTree();
     else nn->right=NULL;
 }

for level order input you have to do in same manner as done in level order Traversal

node buildTree() {*

```
   int d;*
```
```
   cin >> d;*
```
```
   node*root = new node(d);*
```
```
   queue<node*>q;*
```
```
   q.push(root);*
```
```
   while (!q.empty()) {*
```
```
       node*f = q.front();*
```
```
       q.pop();*
```
```
       cin >> d;*
```
```
       if (d != -1) {*
```

           f->left = new node(d); q.push(f->left);*

```
       }*
```
```
       else f->left = NULL;*
```
```
       cin >> d;*
```
```
       if (d != -1) {*
```

           f->right = new node(d); q.push(f->right);*

```
       }*
```
```
       else f->right = NULL;*
```
```
   }*
```
```
   return root;*
```
}*

rachitbansal2500 · June 5, 2020, 6:55am

Please explain the second code

asaurabh_26 · June 5, 2020, 7:10am

2nd one is same as levelorder traversal
have you done Levelorder Traversal if not then do that first
here i make a queue
initially push root to that
then i take input left and right child of current node and then also insert them to queue as well

asaurabh_26 · June 28, 2020, 3:54am

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