class Solution:
    def isCousins(self, root: TreeNode, x: int, y: int) -> bool:
        d = {}

        def dfs(node, k):
            if node != None:
                if node.left != None:
                    d[node.left.val] = [node, k+1]
                    dfs(node.left, k+1)
                if node.right != None:
                    d[node.right.val] = [node, k+1]
                    dfs(node.right, k+1)

        dfs(root, 0)
        return x in d and y in d and (d[x][1] == d[y][1] and d[x][0] != d[y][0])