Check for Children Sum Property in a Binary Tree

Given a binary tree, write a function that returns true if the tree satisfies below property.

For every node, data value must be equal to sum of data values in left and right children. Consider data value as 0 for NULL children.

Solution:

    /* returns 1 if children sum property holds for the given

    node and both of its children*/

    int isSumProperty(Node node)

    {

          

        /* left_data is left child data and right_data is for right

           child data*/

        int left_data = 0, right_data = 0;

  

        /* If node is NULL or it's a leaf node then

        return true */

        if (node == null

                || (node.left == null && node.right == null))

            return 1;

        else

        {

             

            /* If left child is not present then 0 is used

               as data of left child */

            if (node.left != null)

                left_data = node.left.data;

  

            /* If right child is not present then 0 is used

               as data of right child */

            if (node.right != null)

                right_data = node.right.data;

  

            /* if the node and both of its children satisfy the

               property return 1 else 0*/

            if ((node.data == left_data + right_data)

                    && (isSumProperty(node.left)!=0)

                    && isSumProperty(node.right)!=0)

                return 1;

            else

                return 0;

        }

    }