Given the root of a binary tree, return the inorder traversal of its nodes' values.
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Example 1:
\n![\"\"](\"https://assets.leetcode.com/uploads/2020/09/15/inorder_1.jpg\")
\n\nInput: root = [1,null,2,3]\nOutput: [1,3,2]\n\n\n
Example 2:
\n\n\nInput: root = []\nOutput: []\n\n\n
Example 3:
\n\n\nInput: root = [1]\nOutput: [1]\n\n\n
\n
Constraints:
\n\n[0, 100].-100 <= Node.val <= 100\nFollow up: Recursive solution is trivial, could you do it iteratively?", "translatedTitle": null, "translatedContent": null, "isPaidOnly": false, "difficulty": "Easy", "likes": 12811, "dislikes": 696, "isLiked": null, "similarQuestions": "[{\"title\": \"Validate Binary Search Tree\", \"titleSlug\": \"validate-binary-search-tree\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Binary Tree Preorder Traversal\", \"titleSlug\": \"binary-tree-preorder-traversal\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Binary Tree Postorder Traversal\", \"titleSlug\": \"binary-tree-postorder-traversal\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Binary Search Tree Iterator\", \"titleSlug\": \"binary-search-tree-iterator\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Kth Smallest Element in a BST\", \"titleSlug\": \"kth-smallest-element-in-a-bst\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Closest Binary Search Tree Value II\", \"titleSlug\": \"closest-binary-search-tree-value-ii\", \"difficulty\": \"Hard\", \"translatedTitle\": null}, {\"title\": \"Inorder Successor in BST\", \"titleSlug\": \"inorder-successor-in-bst\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Convert Binary Search Tree to Sorted Doubly Linked List\", \"titleSlug\": \"convert-binary-search-tree-to-sorted-doubly-linked-list\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Minimum Distance Between BST Nodes\", \"titleSlug\": \"minimum-distance-between-bst-nodes\", \"difficulty\": \"Easy\", \"translatedTitle\": null}]", "exampleTestcases": "[1,null,2,3]\n[]\n[1]", "categoryTitle": "Algorithms", "contributors": [], "topicTags": [ { "name": "Stack", "slug": "stack", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Tree", "slug": "tree", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Depth-First Search", "slug": "depth-first-search", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Binary Tree", "slug": "binary-tree", "translatedName": null, "__typename": "TopicTagNode" } ], "companyTagStats": null, "codeSnippets": [ { "lang": "C++", "langSlug": "cpp", "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n * int val;\n * TreeNode *left;\n * TreeNode *right;\n * TreeNode() : val(0), left(nullptr), right(nullptr) {}\n * TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}\n * TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}\n * };\n */\nclass Solution {\npublic:\n vector
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