Sum of Root To Leaf Binary Numbers.java

// Runtime: 0 ms (Top 100.0%) | Memory: 41.80 MB (Top 51.65%)

class Solution {
    public int sumRootToLeaf(TreeNode root) {
        return sumRootToLeaf(root, 0);
    }
    public int sumRootToLeaf(TreeNode root, int sum){
        if(root == null) return 0;
        sum = (2 * sum) + root.val;
        if(root.left == null && root.right == null) return sum;
        return sumRootToLeaf(root.left, sum) + sumRootToLeaf(root.right, sum);
    }
}