leetcode 872 Leaf-Similar Trees

python:

class Solution:
    def leafSimilar(self, root1, root2):
        """
        :type root1: TreeNode
        :type root2: TreeNode
        :rtype: bool
        """
        def leaf(root):
            if not root:
                return []
            if not (root.left or root.right):
                return [root.val]
            return leaf(root.left) + leaf(root.right)
        return leaf(root1) == leaf(root2)

class Solution {
public:
    bool leafSimilar(TreeNode* root1, TreeNode* root2) {
        vector<int> le1;
        vector<int> le2;
        leaf(le1, root1);
        leaf(le2, root2);
        return le1 == le2;
    }
    
    void leaf(vector<int> &le, TreeNode* root){
        if(root == nullptr)
            return;
        leaf(le, root->left);
        if(root->left == nullptr && root->right == nullptr)
            le.push_back(root->val);
        leaf(le, root->right);
    }
};