# Random Wits

Life is too short for a diary

\$ random wits
├── tags

├── bookshelf

├── resources

├── quotes

├── habits

# Posts Tagged “code”

Tue 02 Nov 2021

## Coin Change solution leetcode

It's one of the most popular questions on leetcode that seems very easy at first. Coin change is a classic dynamic programming problem. I will proceed with an obvious (albeit wrong) solution and subsequently proceed to an efficient correct solution.

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money. Return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1. You may assume that you have an infinite number of each kind of coin...

Sun 12 Sep 2021

## Maximum Subarray

There's an interesting problem I recently solved on leetcode based on dynamic programming. My Github repository contains list of all problems that I have solved. I often start with a brute force approach without fretting about time complexity. Later I try to improve my algorithm for a better efficient solution.

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. A subarray is a contiguous part of an array.1

..

Sun 10 Nov 2019

## Getting started with Graph Part 1

Graph are data structures made of vertices & edges. There are lots of interesting problems that can be solved using graphs. Part 1 covers the basic for creating a template for graph data structure.

First we need to create a vertex. A vertex is a fundamental unit of graph. A graph is a set of points (vertices) connected by lines (edges)..

Sat 07 Sep 2019

## Recursively sort a array

I recently came across a simple telephonic interview problem. The problem was to sort an array recursively. But even numbers need to be placed before odd numbers. At first glance it was obvious that it was a simple case of implementation of merge sort.

Problem Statement

Given an input array, produce the following output array…..

Tue 08 Jan 2019

## Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list.1. The new list should be made by splicing together the nodes of the first two lists.

It’s an easy problem in Leetcode for practicing linked list. It’s similar to the merge step of the Merge sort. ..

Tue 13 Nov 2018

## Three Sum Problem

Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.1

..

Fri 20 Nov 2015

## Quickly sort large file in linear time

Any deterministic general sorting algorithm has average case time complexity $\Omega(n\log{}n)$ . However, certain sorting algorithm can run faster in $O(n)$ but with limitation. Instead of comparision-based sort, each element is looked individually by its value. Radix sort is one fine example of integer sorting.

Suppose, we have large directory containing names of people in random order. The names need not be distinct. We need to sort the name in the ascending order. Also our algorithm should run in linear time. A sample of the input file is shown below...

Sun 04 May 2014

## Digging on the codes of the Past

Different religion tells us about plethora of beautiful tales about the genesis of humans. We humans, like any other trivial species, descended not from heaven (sigh!) but due to mitosis in single cell organisms.

Such a long odysseys of humans is replete with footprints of the past. In these footprints we try to decipher bits and pieces of lives of our ancestors.While the universe is pretty old (3.7987 billion years and counting), it has been only few million years since the chapter of humans commenced. We had come a long way since...

Wed 06 Nov 2013

## Why I never close Emacs

I once complained to my friend of his desktop on his computer. His desktop was a tangled mess of icons. "It's easier this way.", he chuckled, "I can quickly find all the softwares I need.". I showed him my desktop which was spick and span."Doesn't it consumes time in finding the softwares you need?", he asked.

I told him I have all the softwares I need on my desktop. His eyes rolled down my screen until they stumbled upon a solo icon of emacs. “You just use one software?”, he asked.”Mostly, yes”, I said. “What about editing, browsing, music, etc?”, he asked. “I do it all in emacs.”, I quipped. Before he raised his eyebrows, I explained to him why emacs is informally called as a complete operating system and why I never close emacs...

Fri 18 Oct 2013

## How ViM Saved My Day

It was just another day in Gurgaon. The hot scorching sun was parading the city. The inescapable life of riding with the autowalas is the common sight of this concrete jungle. Though I am a FOSS enthusiast, my first job landed me to just another India's IT company. I vividly remember the countless occasions when ViM saved my day.

I mostly received rudimentary tasks in early days of my work. I received one such task just few days after my joining. I was slouching on my chair when I heard this commanding voice...

Tue 10 Sep 2013

## Why hacking is good

Once a friend of mine asked if I could Hack. I asked him what he meant by hacking. Bemused at such a lame question he replied, "Don't you know what hacking is?". On insisting he reluctantly explained, "breaking into website or stealing passwords of Facebook, etc". I was crestfallen at the rampant misconception about hacking.

Often we read news of hackers breaking into websites siphoning millions of dollars. Such news not only create pervasive fear of hacking but also glorify such malicious activities...

I’ll be using wvdial to configure the internet. It’s likely that your system will have the package pre installed. Otherwise you can manyally download it from here...