<p>Given two binary search trees <code>root1</code> and <code>root2</code>, return <em>a list containing all the integers from both trees sorted in <strong>ascending</strong> order</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2019/12/18/q2-e1.png" style="width: 457px; height: 207px;" />
<pre>
<strong>Input:</strong> root1 = [2,1,4], root2 = [1,0,3]
<strong>Output:</strong> [0,1,1,2,3,4]
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2019/12/18/q2-e5-.png" style="width: 352px; height: 197px;" />
<pre>
<strong>Input:</strong> root1 = [1,null,8], root2 = [8,1]
<strong>Output:</strong> [1,1,8,8]
</pre>

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

<ul>
	<li>The number of nodes in each tree is in the range <code>[0, 5000]</code>.</li>
	<li><code>-10<sup>5</sup> &lt;= Node.val &lt;= 10<sup>5</sup></code></li>
</ul>

/**
 * 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 {
private:
    vector<int> inorderTraversal(TreeNode* root) {
        vector<int> ans;
        if(root==NULL){
            return ans;
        }

        TreeNode* curr = root;

        while(curr){
            if(curr->left){
                TreeNode* prev = curr->left;
                while(prev->right){
                    prev = prev->right;
                }
                prev->right = curr;

                TreeNode* temp = curr;
                curr = curr->left;
                temp->left = NULL;
            }
            else{
                ans.push_back(curr->val);
                curr = curr->right;
            }
        }

        return ans;
    }

    void merge(vector<int>& arr1, vector<int>& arr2, vector<int>& ans){
        int i = 0;
        int j = 0;
        while(i<arr1.size() && j<arr2.size()){
            if(arr1[i]<arr2[j]){
                ans.push_back(arr1[i]);
                i++;
            }
            else{
                ans.push_back(arr2[j]);
                j++;
            }
        }
        while(i<arr1.size()){
            ans.push_back(arr1[i]);
            i++;
        }
        while(j<arr2.size()){
            ans.push_back(arr2[j]);
            j++;
        }
    }    
public:
    vector<int> getAllElements(TreeNode* root1, TreeNode* root2) {
        vector<int> in1 = inorderTraversal(root1);
        vector<int> in2 = inorderTraversal(root2);
        vector<int> ans;
        merge(in1,in2,ans);
        return ans;
    }
};
64599