Arrays

The problem involves counting islands in a 2D grid of ‘1’s (land) and ‘0’s (water). An efficient way to do this is by using Depth-First Search (DFS) to mark visited land as ‘0’. Two approaches are discussed: a brute-force method tracking visited cells and an optimized method that modifies the grid to reduce space complexity.

In the given problem statement, we have a string s and a dictionary wordDict containing a list of words. We need to determine if s can be segmented into a space-separated sequence of dictionary words. The tricky part of this problem is ensuring that every segment of the string matches words from the dictionary. A brute-force approach could generate all possible segmentations, but that would be highly inefficient. Input: s = “studyalgorithms”wordDict = [“study”, “algorithms”]Output: trueExplanation: Since “studyalgorithms” can be split into “study” and “algorithms”, both of which are in …

In this problem, we are given a list of non-overlapping intervals sorted by their start times, along with a new interval. The goal is to insert the new interval into the list while ensuring the intervals remain non-overlapping and sorted. If necessary, overlapping intervals should be merged. The tricky part of this problem lies in handling overlapping intervals efficiently while maintaining the sorted order. We also need to consider edge cases, such as when the new interval does not overlap with any existing intervals or when it encompasses multiple intervals. …

In this blog post, we’ll explore the “Maximum Product Subarray” problem, where our task is to find the contiguous subarray within an array that yields the maximum product. We’ll discuss the problem statement in detail and explore two approaches: the brute force solution and an optimized solution using dynamic programming techniques.

Given an array of positive integers with some zeroes. You need to move all the zeroes to the end without changing the relative order of non-zero elements. A unique solution makes this problem really easy to understand.

Binary Search is a fabulous concept that can be used to narrow down the search range. One such problem on LeetCode explores this domain where you need to find the correct position to insert the element in a sorted array

Small problems like these often become a part of larger complex problems. You are given an array and for each integer you need to find out the number of smaller numbers than itself. One technique is to compare each element with every other element. Another efficient approach would be to use the counting sort approach.

Always make sure that we understand the problem statement first. There is an array of integers nums and we need to determine the number of good pairs. A pair (i , j ) is said to be good, if nums[i] == nums[j] and i < j. We need to determine how many pairs can we form that hold this condition. Let us look at some sample test cases: Input: nums = [ 1 , 2 , 3 , 1 , 1 , 3 ]Output: 4Explanation:There are 4 good pairs. (0 …

Given a sorted array and a target element, find its first and last index.

Let us try to understand this problem statement first. It is actually very verbose. We will try to simplify it as much as possible. Christy wants to give chocolates to her colleagues, and at the same time tries to ensure that everyone has equal chocolates at the end. To achieve this she either gives 1,2, or 5 chocolates to everyone except any one individual. Every-time she does this, it is counted as 1 operation. We need to make sure that Christy can achieve this task in the minimum number of …