Given a Binary Tree. Check whether it is a Sum Tree or not.
A Binary Tree is a Sum Tree in which value of each node x is equal to sum of nodes present in its left subtree and right subtree . An empty tree is also a Sum Tree as sum of an empty tree can be considered to be 0. A leaf node is also considered as a Sum Tree.
Input: 3 / \ 1 2 Output: 1 Explanation: The given tree is a sum tree so return a boolean true.
Input: 10 / \ 20 30 / \ 10 10 Output: 0 Explanation: The given tree is not a sum tree. For the root node, sum of elements in left subtree is 40 and sum of elements in right subtree is 30. Root element = 10 which is not equal to 30+40.
You dont need to read input or print anything. Complete the function isSumTree() which takes root node as input parameter and returns true if the tree is a SumTree else it returns false.
Expected Time Complexity: O(N)
Expected Auxiliary Space: O(Height of the Tree)
1 ≤ number of nodes ≤ 104