Leaf-Similar Trees
<p>Consider all the leaves of a binary tree, from&nbsp;left to right order, the values of those&nbsp;leaves form a <strong>leaf value sequence</strong><em>.</em></p>

<p><img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0800-0899/0872.Leaf-Similar%20Trees/images/tree.png" style="width: 400px; height: 336px;" /></p>

<p>For example, in the given tree above, the leaf value sequence is <code>(6, 7, 4, 9, 8)</code>.</p>

<p>Two binary trees are considered <em>leaf-similar</em>&nbsp;if their leaf value sequence is the same.</p>

<p>Return <code>true</code> if and only if the two given trees with head nodes <code>root1</code> and <code>root2</code> are leaf-similar.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0800-0899/0872.Leaf-Similar%20Trees/images/leaf-similar-1.jpg" style="width: 600px; height: 237px;" />
<pre>
<strong>Input:</strong> root1 = [3,5,1,6,2,9,8,null,null,7,4], root2 = [3,5,1,6,7,4,2,null,null,null,null,null,null,9,8]
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0800-0899/0872.Leaf-Similar%20Trees/images/leaf-similar-2.jpg" style="width: 300px; height: 110px;" />
<pre>
<strong>Input:</strong> root1 = [1,2,3], root2 = [1,3,2]
<strong>Output:</strong> false
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in each tree will be in the range <code>[1, 200]</code>.</li>
	<li>Both of the given trees will have values in the range <code>[0, 200]</code>.</li>
</ul>
Tree; Depth-First Search; Binary Tree
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool leafSimilar(TreeNode* root1, TreeNode* root2) {
        vector<int> l1, l2;
        dfs(root1, l1);
        dfs(root2, l2);
        return l1 == l2;
    }

    void dfs(TreeNode* root, vector<int>& nums) {
        if (root->left == root->right) {
            nums.push_back(root->val);
            return;
        }
        if (root->left) {
            dfs(root->left, nums);
        }
        if (root->right) {
            dfs(root->right, nums);
        }
    }
};
