Sum Tree

Problem Statement

Pattern:

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Check if BT is Sum Tree

Sum Tree | Practice | GeeksforGeeks

boolean isSum = true;
 
boolean isLeaf (Node root) {return (root.left == null && root.right == null);}
 
int check(Node root) {
	if (root == null || !isSum) return 0;
 
	int lsum = check(root.left);
	int rsum = check(root.right);
	
	if(!isLeaf(root) && (root.data != lsum+rsum)) 
		isSum = false;
	
	return lsum+rsum+root.data;
}
 
boolean isSumTree(Node root)
{
	check(root);
	return isSum;
}

Transform to Sum tree

Transform to Sum Tree | Practice | GeeksforGeeks

public int sum (Node root) {
	if(root == null) return 0;
	
	int lSum = sum(root.left);
	int rSum = sum(root.right);
	
	int rootVal = root.data;
	root.data = lSum + rSum;
	return rootVal +lSum + rSum;
}
 
public void toSumTree(Node root){
	 //add code here.
	 sum(root);
}