Check for Children-Sum property in Binary Tree in C

March 19, 2025

Children-Sum property in Binary Tree

Children-Sum property says that for each node sum of its left and right children should be equal to node value.

Also, following assumptions are to be kept in mind while recursively traversing tree

  1. A leaf node satisfies children sum property because leaf nodes don’t have any child nodes.
  2. An Empty tree satisfies Children sum property.
Check for Children-Sum property in Binary Tree in C-1

Children Sum Property In Binary Tree

Algorithm :

  • Traverse the tree.
  • For every node in tree check whether the value in root node equals the sum of its leftchild and rightchild.
  • If yes continue from Step 1 Until, root becomes Null i.e,  root==NULL
  • If No return 0.
Check for Children-Sum property in Binary Tree in C

Check whether two tree are identical

Spiral Order traversal of Tree

Check If binary tree if Foldable or not

Sum of all nodes in Binary Tree

Lowest Common Ancestor in Binary Tree

Code in C based on above approach

Run 
#include <stdio.h>
#include <stdlib.h>

struct node
{
  int data;
  struct node *left;
  struct node *right;
};

int isSumProperty (struct node *node)
{
  int left_data = 0, right_data = 0;

  if (node == NULL || (node->left == NULL && node->right == NULL))
    return 1;
  else
    {
      if (node->left != NULL)
	left_data = node->left->data;

      if (node->right != NULL)
	right_data = node->right->data;

      if ((node->data == left_data + right_data) && isSumProperty (node->left)
	  && isSumProperty (node->right))
	return 1;
      else
	return 0;
    }
}

struct node *newNode (int data)
{
  struct node *node = (struct node *) malloc (sizeof (struct node));
  node->data = data;
  node->left = NULL;
  node->right = NULL;
  return (node);
}

int main ()
{
  struct node *root = newNode (10);
  root->left = newNode (8);
  root->right = newNode (2);
  root->left->left = newNode (3);
  root->left->right = newNode (5);
  root->right->right = newNode (2);
  if (isSumProperty (root))
    printf ("The given tree satisfies the children sum property ");
  else
    printf ("The given tree does not satisfy the children sum property ");

  return 0;
}

Output:

The given tree satisfies the children sum property