AlphonseTask

Input Format:

Each line of consists of description of Tree in level order fashion with N meaning NULL.
For eg: 1 2 N 3 4
```
   1
  / \
 2   N
/ \
3  4
```

Each line consiss of final colored trees wih 'R','G' and 'B' for (Red,Green and Blue colors) in a preoder fashion
For eg: B R B R
```
   B
  / \
  R   N
/ \
B  R
```

Did bounary traversal of each node starting from left boundary followd by leaves of left and right child respectively and finally right boundary one by one.
Took a color Variable and pass it as refrence after every coloring updated its value altrantively to Red and Blue based on previous value.
Finally performed preorder of resulting tree and store it as string.
By Default every node is marked as 'G' (GREEN)

Time Complexity
- O(length of input) for the conversion of level order traversal of Tree
- O(N) N=no of nodes in binary tree, boundary traversal of Tree
- O(N) N=no of nodes in binary tree, preorder traversal of Tree
- Total: O(2*N)+O(length of input)
Space Complexity
- O(length of input) queue for storing level order traversal of Tree
- O(height of tree) stack space for boundry traversal of Tree
- O(height of tree) stack space for preorder traversal of Tree
- Total: O(2*height of tree)+O(length of input)