### Validate Binary Search Tree

Link to leetcode problem definition Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as…

Link to leetcode problem definition Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as…

A simple demo of creating linked list from array

Use stream api to quickly sort a 2D array in Java.

The below code snippet demonstrates how to transform a set collection to list. Simply pass a set in constructor of List:

Link to leetcode problem definition Given a sorted array and a target value, return the index if the target is found. If not, return the…

link to leetcode problem definition Given a string s and a string t, check if s is subsequence of t. A subsequence of a string is a new…

link to leetcode problem definition You are given coins of different denominations and a total amount of money. Write a function to compute…

Linked list problem that can be solved in O(1) Write a function to delete a node (except the tail) in a singly linked list, given only…

Inspiration of this problem comes from Max Howel's interview experience with Google described in this tweet. Lets jump to the problem The…

In these series I will be posting my solutions to leetcode questions from June challenge. Navigate to the linked pages below to read…

Link to leedcode problem definition Suppose you have a random list of people standing in a queue. Each person is described by a pair of…

link to leedcode problem definition Write a function that reverses a string. The input string is given as an array of characters char[]. Do…

link to leetcode problem definition There are 2N people a company is planning to interview. The cost of flying the i-th person to city A is…

Another interesting leetcode problem that comes up often in Apple and Google interviews. Given a positive integer n, break it into the sum…

Another interesting leetcode problem that comes up often in Apple and Google interviews. Given a positive integer n, break it into the sum…

Nice graph problem from leetcode biweekly contest. As majority of graph problems this one can be solved with Breadth First Search as well…

Dynamic programming solutions are just a pleasure to read! Here is another one from Biweekly leetcode contest 26 to a problem that can be…

1447 Simplified fractions Given an integer n, return a list of all simplified fractions between 0 and 1 (exclusive) such that the…

How Mac OS Catalina update broke my pip, python set up. I finally decided it is time to upgrade Mac OS Catalina, the whole process was in…

Another mind blowing solution with dynamic programming to LeetCode problem number 26 from 30 day challenge Problem statement: Given a 2D…