Month: January 2021

Invert Binary Tree

Inverting a Binary Tree is a problem asked in a lot of interviews and we will be tackling it in a simple but efficient manner. Any tree-related problem should be attempted to be solved in a recursive approach since Tree is a localized data structure i.e small trees make up large trees.

Isomorphic Strings

Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.

Next Closest Time

Given a time represented in the format “HH:MM”, Form the next closest time by reusing the current digits. There is no limit on how many times a digit can be reused. You may assume the given input string is always valid. For example, “01:34”, “12:09” are all valid. “1:34”, “12:9” are all invalid.