def binaryTreePathsRecu(root, path, result):
    if (node is None):
        return
    if (node.left is node.right is None):
        ans = ''
        for n in path:
            ans += (str(n.val) + '->')
        result.append((ans + str(node.val)))
    if node.left:
        path.append(node)
        self.binaryTreePathsRecu(node.left, path, result)
        path.pop()
    if node.right:
        path.append(node)
        self.binaryTreePathsRecu(node.right, path, result)
        path.pop()
def binaryTreePathsRecu(root, path, result):
    if (node is None):
        return
    if (node.left is node.right is None):
        ans = 
        for n in path:
            ans += (str(n.val) + '->')
        result.append((ans + str(node.val)))
    if node.left:
        path.append(node)
        self.binaryTreePathsRecu(node.left, path, result)
        path.pop()
    if node.right:
        path.append(node)
        self.binaryTreePathsRecu(node.right, path, result)
        path.pop()