Engineeringstepstone

  LinkedList implementation using Array Structure -- React   LinkedList implementation and invoke it through React Node definition LinkedList implementation Lets add methods to it Not enough, Lets show the behavior in UI  

 Recursion, tail optimization and memoization are important piece of Functional programming. Before jumping into solving complex solutions, I slip on basic structure of recursion lot of times. What is base case and what is recursive step? When I ask most recursive person at home, got the answer as "until I need a charge". Seriously??? I don't know what algorithm it is!!???. It moves all around without any pattern until completely got drained. ☺ May be it is the algorithm... So finding the base case says when to stop.   Another programming example: We are given a denomination of coins/ currency notes and amount of value. We need to identify the minimum number of coins/ currency notes required for calculating that amount. For the amount $3.15, we need to pick up 12 quarters, 1 dime and 1 nickel. So total number of coins is 14 coins. The base case here -> if total of value is equal to the amount required. The recursive step -> pick a higher denomination available to re...

Sometimes we fall into illusion of performant code. It happened to me recently. This is what the case. Problem: Identify unique values in an array of values where all items appear exactly twice but one.  Super simple right? I wrote the following two different solutions . Solution 1:           var singleNumber = function(nums) {     return Object.keys(nums.reduce((acc, item) => {        if(typeof(acc[item]) !== 'undefined') {            delete acc[item];        } else {            acc[item] = item;        }         return acc;     },{}))[0]; }; Solution 2:       var singleNumber = function(nums) {         return nums.reduce((acc, item) => acc ^ item);      };   What your choice? mine was the first one. When I compare...

     HTML      CSS      td {        width: 2em;      }     JS let data = { rows: null, cols: null, matrix: null }; function generateString(n, m) { for(let i = 0, str=''; i arr.map(el => ` ${el} `).join(''); const rows = data => data.map(datum => ` ${row(datum)} `).join(''); return ` ${rows(matrix)} `; } document.getElementById('rows').addEventListener('change', ({target: {value}}) => { data.rows = parseInt(value) || 0; if ( data.cols ) { data.matrix = generateMatrix(data.rows, data.cols); } }); document.getElementById('cols').addEventListener('change', ({target: {value}}) => { data.cols = parseInt(value) || 0; if ( data.rows ) { data.matrix = generateMatrix(data.rows, data.cols); } }); document.getElementById('generate').addEventListener('click', e => { if(data.matrix) document.getElementById('r...

Almost late. I thought checking mails won't take much time. But it is! Grab the bag, is Id there? Get the lunch box and ... where is my car key??? checking every where I couldn't recollect where I kept it. Checked the book shelf, TV stand, my last day pant and bathroom. OMG, why I am doing this mistake every time? Bigger house is convenient as well as discomfort. How am I going to locate the keys??? I stopped for a while. And started recollecting the moment when I entered home after my last drive. But with oscillation of various things in my mind, I couldn't focus. There is a meeting by 10 and I should go office at least by 9:50. "Why do you leave the key in dining table? Change the habit, keep the key all times in key holder" - It is Subha with car keys. She is right. This is not the first time she is talking about it. "OK", I haven't even stopped and thanked her. Ran to start the car. And after a few weeks, she was out. I was searching for...

Choo choo... running behind friends on the street was fun. When I wanted to play the game with kids, they enjoyed it too. Adult next to us looking at weird. No one plays such games on street now a days. But try with your kids and neighboring kids and share how it energizes. We were 5 initially formed the chain. I was the Engine for first few games. I stood in the front and wait for the coaches to join. Sai krishna (my son) follows me every time, happily catches my shirt and said "I am behind you. Hey Engine, start start. Choo choo....". "Hey train wait...." - it was my daughter Danya sri catches Sai krishna shirt and formed next coach. We were riding on the street and all eyes on us. There comes our neighboring kid Sakthi. She follows Danya and now the train is little bigger. We were running on the street happily.  Then to make some fun in the middle, Engine started going fast and Danya missed to pick it up immediately. "Hey Engine, wait......