function sumRootToLeaf(root: TreeNode | null): number {
if(!root) return 0
let total = 0
function dfs(node: TreeNode, sum: number) {
if(!node.left && !node.right) {
console.log(sum)
total += sum
return
}
if(node.left) dfs(node.left, (sum << 1) + node.left.val)
if(node.right) dfs(node.right, (sum << 1) + node.right.val)
}
dfs(root, root.val)
return total
};