In this tutorial, I am going to discuss binary tree postorder traversal. How to implement binary tree postorder traversal with and without recursion.
Given the root of a binary tree, write a code to return the postorder traversal of its node’s values.
In this problem, We have to write a code to sort a stack using recursion. We have to sort in a descending order (Top of the stack has the greatest element).
We don’t have to use any loop constructs ( for, while etc) or additional data structure.
For Example –
In this example, You can see after sorting the stack, the element which has greater value is at the top of the stack.
In this tutorial, I am going to discuss a problem Is Subsequence (check if a string is subsequence of another string).
Given two strings str1 and str2, check if str1 is a subsequence of str2. Both strings consists only of lowercase characters.
Example 1:
Input: str1 = “abc”, str2 = “ahbgdc”
Output: true
Example 2:
Input: s = “axc”, t = “ahbgdc”
Output: false