Leetcode•May 18, 2025
Binary Tree Inorder Traversal
Hazrat Ali
Leetcode
Given the root of a binary tree, return the inorder traversal of its nodes' values.
Example 1:
Input: root = [1,null,2,3]
Output: [1,3,2]
Explanation:
Example 2:
Input: root = [1,2,3,4,5,null,8,null,null,6,7,9]
Output: [4,2,6,5,7,1,3,9,8]
Explanation:
Example 3:
Input: root = []
Output: []
Example 4:
Input: root = [1]
Output: [1]
Solution
const inorderTraversal = root => {
const result = [];
const stack = [];
let current = root;
while (stack.length || current) {
if (current) {
stack.push(current);
current = current.left;
} else {
current = stack.pop();
result.push(current.val);
current = current.right;
}
}
return result;
};