Category Archives: ANDROID

Given a string, return the length of the longest palindromic subsequence in the string- Asked by Google

By | December 21, 2023

Given a string, return the length of the longest palindromic subsequence in the string. For example, given the following string: MAPTPTMTPA Return 7, since the longest palindromic subsequence in the string is APTMTPA. Recall that a subsequence of a string does not have to be contiguous! Your algorithm should run in O(n^2) time and space.… Read More »

Implement a PrefixMapSum class with the following methods

By | July 5, 2023

insert(key: str, value: int): Set a given key’s value in the map. If the key already exists, overwrite the value. sum(prefix: str): Return the sum of all values of keys that begin with a given prefix. For example, you should be able to run the following code: mapsum.insert(“columnar”, 3) assert mapsum.sum(“col”) == 3 mapsum.insert(“column”, 2)… Read More »

Problem: You are given N identical eggs and access to a building with k floors. Your task is to find the lowest floor that will cause an egg to break, if dropped from that floor.

By | July 2, 2023

You are given N identical eggs and access to a building with k floors. Your task is to find the lowest floor that will cause an egg to break, if dropped from that floor. Once an egg breaks, it cannot be dropped again. If an egg breaks when dropped from the xth floor, you can… Read More »

Create an algorithm that arranges them in order to form the largest possible integer

By | July 2, 2023

Given a list of numbers, create an algorithm that arranges them in order to form the largest possible integer. For example, given [10, 7, 76, 415], you should return 77641510. Javascript function largestNumber(nums) {  nums.sort((a, b) => {    const order1 = String(a) + String(b);    const order2 = String(b) + String(a);    return order2.localeCompare(order1); … Read More »

Write a program to compute the in-order traversal of a binary tree using O(1) space.

By | June 25, 2023

Python Java Javascript These implementations use the Morris Traversal algorithm to perform in-order traversal without using any additional space other than O(1). The algorithm establishes temporary links between nodes and their predecessors, allowing efficient traversal and processing of the tree nodes. Note: The code examples assume that the tree nodes have a val, left, and… Read More »

Flutter vs. React Native: Unraveling the Performance Battle

By | June 25, 2023

Introduction: When it comes to developing cross-platform mobile applications, Flutter and React Native have emerged as the two dominant frameworks. As developers seek to create high-performing apps, it’s crucial to understand the performance capabilities of each framework. In this article, we will delve into the performance aspects of Flutter and React Native, examining their strengths… Read More »

Different ways of making rounded corner images in flutter

By | June 25, 2023

Example 1: ClipRRect dartCopy codeClipRRect( borderRadius: BorderRadius.circular(10.0), child: Image.asset(‘assets/images/image.jpg’), ) In this example, the ClipRRect widget is used to clip the child Image with rounded corners. The borderRadius property defines the radius of the corners. Example 2: BoxDecoration dartCopy codeContainer( decoration: BoxDecoration( borderRadius: BorderRadius.circular(10.0), image: DecorationImage( image: AssetImage(‘assets/images/image.jpg’), fit: BoxFit.cover, ), ), ) Here, a… Read More »

Given an absolute pathname that may have . or .. as part of it, return the shortest standardized path

By | June 25, 2023

Given an absolute pathname that may have . or .. as part of it, return the shortest standardized path. For example, given “/usr/bin/../bin/./scripts/../”, return “/usr/bin/”. To obtain the shortest standardized path from an absolute pathname that may contain “.” or “..” as part of it, you can follow these steps: Here’s an example Python code… Read More »

Riverpod in Flutter – Simplest Example Ever

By | June 22, 2023

In this example, we create a simple Flutter application that displays a counter and increments the count when a FloatingActionButton is pressed. The state management is handled by Riverpod. Here’s a breakdown of the code: When you run this code, you will see a simple app with an app bar, a counter in the center… Read More »

Connect 4 is a game where opponents take turns dropping red or black discs into a 7 x 6 vertically suspended grid.

By | June 22, 2023

The game ends either when one player creates a line of four consecutive discs of their color (horizontally, vertically, or diagonally), or when there are no more spots left in the grid. Design and implement Connect 4. To design and implement Connect 4, we can follow these steps: Here’s an example implementation of Connect 4… Read More »

Roman numeral format to decimal.

By | June 22, 2023

Given a number in Roman numeral format, convert it to decimal. The values of Roman numerals are as follows: { ‘M’: 1000, ‘D’: 500, ‘C’: 100, ‘L’: 50, ‘X’: 10, ‘V’: 5, ‘I’: 1 } In addition, note that the Roman numeral system uses subtractive notation for numbers such as IV and XL. For the… Read More »

Problem Solving – IP addresses must follow the format A.B.C.D, where A, B, C, and D are numbers between 0 and 255.

By | June 19, 2023

Given a string of digits, generate all possible valid IP address combinations. IP addresses must follow the format A.B.C.D, where A, B, C, and D are numbers between 0 and 255. Zero-prefixed numbers, such as 01 and 065, are not allowed, except for 0 itself. For example, given “2542540123”, you should return [‘254.25.40.123’, ‘254.254.0.123’]. To… Read More »

MVVM in Android – ViewModels, ViewModelScope, Retrofit all with a Simple Example.

By | June 6, 2021

Let’s learn how to implement MVVM in Android. It’s actually really simple. ViewModel is just another class that that implements the main Business Logic. ViewModel is a middle man between your view and your Data class(Repo/any Data Provider). It can be represented simply like this. Here the View just displays the data. ViewModel doesn’t know… Read More »

Theming your App in Flutter using BLoc, Save & Reload

By | December 6, 2020

In this article, we will see how we can use BLoc to Theme your app in Flutter. To understand BLoC with a real world example, you can refer to my previous post on BLoC here. Part 1 Part 1 For this demo also we will need the below plugins If you follow my previous tutorial,… Read More »

How to use YouTube APIs and Play YouTube videos in Flutter.

By | August 27, 2020

In this article we are gonna talk about how to use YouTube API’s and play YouTube videos in Flutter. Watch Video Tutorial Add Dependencies Open pubspec.yaml file in your Flutter project and add below dependencies Now, Let’s create two screens Home Screen Video Player Screen In the HomeScreen we will show the list of videos.… Read More »

Bottom Navigation in Flutter

By | April 18, 2019

This article shows how to implement Bottom navigation using Tabs in Flutter.     Watch Video Tutorial     For that we need to have a TabController and a TabBarView Widget.   Create Tabs   This is our demo tab layout widget. Create a new file name FirstTab.dart and copy the contents into it. You… Read More »

Flutter – Android, iOS , Native communication Simple Demo

By | December 24, 2018

Hello Devs, You know flutter is now a hot topic. Learning flutter will always help in your future career. In this article we will see how we can communicate between Flutter and Android. Watch Video Tutorial MethodChannel Flutter communicate with Native using “MethodChannel“. So you have to create a method channel with a constant as… Read More »

Is Javascript Multithreaded? How it handles asynchronous actions?

By | December 14, 2018

Javascript is a single threaded application. That means you cannot run more than one script at one time to modify DOM or something. But there are something called “Worker Threads” that spans separate threads outside your application that can do complex tasks which is linked by a Callback method. What is a Web Worker? When… Read More »

What is Context in Android and What is the proper way to use it?

By | December 7, 2018

Lets see what a Context is… Context : Current State of the application. Context : Handle of the application. Context : Provides access to the resources, preferences, accessing database etc. Activity inherits from the Context. Context is the most important part of the Android application and its everywhere. If you wrongly use Context, it can… Read More »

Using Content Resolver to List Contacts – Android

By | October 31, 2018

Here is a simple example to list contacts in android using the Content Resolver. Note : You need to have two things before accessing contacts. 1. Contacts Permission in the Android Manifest 2. Ask Runtime permission from the user Code Here is our MainActivity that lists the contacts. MainActivity.java Adapter Class Below is the adapter… Read More »