Find the maximum sum from leaf to root in a binary tree

Given a Binary Tree, find the maximum sum from a leaf to root and return this leaf as well.


The key is from root to leave, add up the node value and pass the sum to the lower levels. 

public static int maxSumFromRootHelper(Node root, int sum){

if(root == null)

return sum;

else{

return Math.max(maxSumFromRootHelper(root.left, root.data + sum),

  maxSumFromRootHelper(root.right, root.data + sum));

}

}

//store the max sum result

static int max_sum = Integer.MIN_VAL;

//store the leaf 

static Node maxNode = null;

public static void findLeaveWithMaxSumFromRoot(Node root, int sum){

if(root == null)

return;

sum = sum + root.data;

if(root.left == null && root.right ==null){

if(sum > max_sum){

max_sum = sum;

maxNode = root;

}

}

else{

findLeaveWithMaxSumFromRoot(root.left, sum);

findLeaveWithMaxSumFromRoot(root.right, sum);

}

}