Click here to see the problem on LeetCode. The problem description is pretty straightforward. We have to return all the nodes’ values following the preorder traversal algorithm. I can assume that you have a basic understanding of Tree data structure. Mainly, there are four types of traversing algorithms in Binary Tree. Preorder traversal is one […]

# Category: LeetCode

## Monotonic Array | LeetCode 896 | Python | Solution

Here is the link to the problem. See the problem description. We have to check the given array is monotonic or not. What is a monotonic array? “An array is monotonic if it is either monotone increasing or monotone decreasing.” line quoted from the problem description. The formula is:For checking increasing monotone of the given […]

## Duplicate Emails | LeetCode 182 | SQL | Solution

This one is a simple SQL problem. Here is the link to this problem. This one is an absolute beginner type problem. We have to query all the duplicates emails from the given table. The name of the table is Person. The code is almost self-explanatory. All SQL keywords are written in uppercase letters. It’s […]

## Contains Duplicate | LeetCode 217 | Python | Solution

Click here to see the problem details. The problem is simple. We have to find at least one duplicate in the given array. If we found any duplicate number, we will return True. Otherwise, we will return False. That’s the simple idea about the problem. And given array’s elements will be integers. Let’s see two […]

## Reverse String | LeetCode 344 | Python | Solution

Click here to see the problem. And read the description and try to understand the problem first. Reverse String is one of the most common problems in computer programming. And this time, the input string is given as an array of characters. We have to return the reverse version of the given array. See the […]

## Largest Number At Least Twice of Others | LeetCode 747 | Python | Solution

Click here to see the problem in LeetCode. And read the problem’s details. This one is a pretty simple problem. We will be given an integer array. We have to find the largest element’s index, which is must be at least twice as much as every other number in the array. If it’s not matched […]

## Linked List Cycle | LeetCode 141 | Python | Solution

Click here to see the problem details. Read the description first. We will be given a Linked List. We have to determine there is any cycle or not in the linked list. It is an easy problem. See the problem details for the visual representation of the cycle in a linked list. Coding Part Generally, […]

## 700. Search in a Binary Search Tree | LeetCode | Python | Solution

Click here to see the problem in LeetCode. Read the description carefully. This one is a pretty easy problem for you if you know how to search on Binary Search Tree (BST). First, we will be given a Binary Search Tree and a value for search. We have to search for the given value in […]

## 35. Search Insert Position | LeetCode | Python | Solution

This one is a binary search-related problem. Click here to see the problem in LeetCode. We will be given a sorted array in ascending order. And a target value. So, what we have to do? We will have to return the index of the target value. If the target value is not in the given […]

## 620. Not Boring Movies | LeetCode | SQL | Solution

This one is database related problem and pretty easy. Click here to see the problem on LeetCode. Read the description and try to understand the problem. Note: I assumed that you have basic knowledge of SQL language. The actual problem is, we have to retrieve data from the database with some condition. We have to […]