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Problem of the day

You have been given two Binary Search Trees ‘root1’ and ‘root2’ of integers and you want to collect all the elements present in both the BSTs.

Your task is to print all the integers from both BSTs sorted in ascending order.

A binary search tree (BST) is a binary tree data structure which has the following properties.

```
• The left subtree of a node contains only nodes with data less than the node’s data.
• The right subtree of a node contains only nodes with data greater than the node’s data.
• Both the left and right subtrees must also be binary search trees.
```

For Example:

```
For the given BSTs:
```

```
The output will be: [2, 2, 5, 7, 7, 10, 10, 16, 16, 20, 20]
```

Detailed explanation

```
The first line contains an integer 'T' which denotes the number of test cases or queries to be run. Then the test cases follow.
The first line of each test case contains the elements of the BST ‘root1’ in the level order form separated by a single space.
The second line of each test case contains the elements of the BST ‘root2’ in the level order form separated by a single space.
If any node does not have a left or right child, take -1 in its place. Refer to the example for further clarification.
Example:
Elements are in the level order form. The input consists of values of nodes separated by a single space in a single line. In case a node is null, we take -1 in its place.
For example, the input for the tree depicted in the below image would be :
```

```
1
2 3
4 -1 5 6
-1 7 -1 -1 -1 -1
-1 -1
Explanation :
Level 1 :
The root node of the tree is 1
Level 2 :
Left child of 1 = 2
Right child of 1 = 3
Level 3 :
Left child of 2 = 4
Right child of 2 = null (-1)
Left child of 3 = 5
Right child of 3 = 6
Level 4 :
Left child of 4 = null (-1)
Right child of 4 = 7
Left child of 5 = null (-1)
Right child of 5 = null (-1)
Left child of 6 = null (-1)
Right child of 6 = null (-1)
Level 5 :
Left child of 7 = null (-1)
Right child of 7 = null (-1)
The first not-null node (of the previous level) is treated as the parent of the first two nodes of the current level. The second not-null node (of the previous level) is treated as the parent node for the next two nodes of the current level and so on.
The input ends when all nodes at the last level are null (-1).
Note :
The above format was just to provide clarity on how the input is formed for a given tree.
The sequence will be put together in a single line separated by a single space. Hence, for the above-depicted tree, the input will be given as:
1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1
```

```
For each test case, print the elements of both binary search trees in ascending order.
Print output of each test case in a separate line.
Note: You are not required to print anything explicitly. It has already been taken care of. Just implement the function.
```

```
1 <= T <= 100
1 <= N1 + N2 <= 5000
0 <= data <= 10^5
Where ‘N1’ is the number of nodes in the binary search tree ‘root1’, ‘N2’ is the number of nodes in the binary search tree ‘root2’, ‘T’ represents the number of test cases and ‘data' denotes data contained in the nodes of the binary search trees.
Time Limit: 1 sec
```

```
1
15 10 20 8 12 16 25 -1 -1 -1 -1 -1 -1 -1 -1
10 -1 90 -1 -1
```

```
8 10 10 12 15 16 20 25 90
```

```
The trees can be represented as follows:
```

```
The nodes of both BST in increasing order are 8 10 10 12 15 16 20 25 90.
```

```
1
10 5 -1 -1 -1
20 -1 -1
```

```
5 10 20
```