Inorder Traversal

Related Problems

• 230. Kth Smallest Element in a BST
  • https://leetcode.com/problems/kth-smallest-element-in-a-bst/
• 897. Increasing Order Search Tree
  • https://leetcode.com/problems/increasing-order-search-tree/solution/

In binary search tree problems (kind of sorted), many problems can be solved with in-order traversal just like iterating through a regular sorted array.

Think this way, a BST (Binary Search Tree) is pretty much equivalent to a sorted array, if a given problem whose data structure is BST can be solved with a sorted array, then it's very likely it can be solved the same way with a BST.

For example, for 230. Kth Smallest Element in a BST, suppose you are to select the Kth smallest element in a sorted array, you just need to iterate through the array (suppose you cannot use index). BST is pretty much equivalent to a sorted array, except that it cannot use index. So just do a in-order traversal to simulate the sorted array iteration.