Ternary string is an interesting problem that could be solved using two pointers techniques. It's a convenient way to keep track of multiple indices. This helps in making decisions based on two values.
You are given a string s such that each its character is either 1, 2, or 3. You have to choose the shortest contiguous substring of s such that it contains each of these three characters at least once. A contiguous substring of string s is a string that can be obtained from s by removing some (possibly zero) characters from the beginning of s and some (possibly zero) characters from the end of s...
Continue reading → Tags : codeforces two pointers java python
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...
Continue reading → Tags : programming leetcode code dp java python
I was an intern working in Upstate New York. Public transport required hopping multiple trains & buses and was woefully tedious. I found some other interns who were willing to split the fare with me for Uber. Even a ride in Uber consumed more than two hours. Occasionally I used to steal a quick nap. After a siesta of a few hours, I had always woken up with a gaggle of laughter. My peers often pulled my leg, "You were snoring like a pig". However, I dismissed my faux pas as just a mere nuisance.
Recently I was listening to a clubhouse talk about snoring1. I always believed that snoring was innocuous. However, I learned that snoring might be a symptom of a disorder like sleep apnea. Since most of us snore or are more likely to snore in the later part of our lives, it would be prudent to delve deeper into the understanding of snoring...
Continue reading → Tags : snoring sleep apnea diary rambling
When the alarm clock breaks my slumber, I roll down on my bed, blindly crawling towards my alarm clock as if it was a bomb to diffuse it. After multiple snoozes, I relinquished my dreams and come to my senses. Gulping water after I wake up is my first activity. Next, I excuse myself to the bathroom for “nature call”. All living things from a simple bacteria to a giant dinosaur needs to perform two basic life function; eat and excrete.
Our world has been ravaged by covid pandemic recently. So it would be apt to talk about viruses. As a child, my imagination often ran wild, wondering how viruses hijacked our bodies, and more importantly did they eat and poop like other microbes?..
Continue reading → Tags : virus diary rambling
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
..Continue reading → Tags : programming leetcode code dp
This is my first time visiting Mexico city, also known as CDMX. Initially I was scared to come here because of Narcos. However during my brief two weeks stay I have felt safe. With my limited Spanish, I decided to book an Airbnb experience for a bike tour.
The tour had a meeting point at Bazar Fusion. Uber is cheap & convenient to commute in Mexico city. On reaching at Bazar Fusion, I had a cappuccinos before hopping on to the bike. The bike was comfortable enough however with no helmet which I didn’t mind. ..
Continue reading → Tags : cdmx mexico travel bike
Do you believe in ghosts? I did when I was a kid. I was infatuated with the paranormal. Sometimes I used to wander around desolate buildings with other kids concocting horror stories. I loquaciously gossiped about ghosts in school which earned me a sizeable audience. I was convinced that someday I would stumble upon an innocuous spirit that would instill some unearthly powers in me.
Vic Tandy, a British engineer, was working at Warwick Laboratory when he thought he saw a ghost. He later said, “I was sweating but cold, and the feeling of depression was noticeable – but there was also something else. It was as though something was in the room with me.” He then claimed to have seen a spirit emerging in his peripheral vision, but when he turned to face the figure, it vanished”. He later went home perplexed...
Continue reading → Tags : diary rambling infrasound
AWS CDK is a great framework to programmatically deploy cloudformation stack. If you are unfamiliar with AWS CDK, I would recommend first to check out Getting started with AWS CDK.
One of the pet peeves I have while designing cloudformation template is redundancy. I have to manually copy-paste the same properties across multiple resources. I wanted to leverage AWS CDK to create an interface that would allow tto dynamically create cloudformation. For the interface, I harked back to the good old CSV file...
Continue reading → Tags : aws cdk cloudformation typescript tutorial
Cloudformation service in AWS allows you to describe an entire set of resources required to make a pipeline. The cloudformation template can be described in JSON or YAML format. Updating the cloudformation template was not a pleasant experience. I wanted to discover alternative ways to generate cloudformation template programmatically.
The CDK library provides you a way to declare the resources in your favorite languages like Java, Javascript, Typescript, and Python. In this tutorial, we will use typescript to generate our cloudformation template...
Continue reading → Tags : aws cdk cloudformation typescript tutorial
What’s a nationality? The idea of the nation-state is pretty modern. Ancient lands were usually under the suzerainty of kings & queens. While most emperors spilled blood to expand their kingdom, the common man was seldom concerned about borders.
Peace of Westphalia was a famous peace treaty in 1648 that ended thirty years war. Historians often cite this as an example of first nation state. It relied on a system of independent states refraining from interference in each other’s domestic affairs and checking each other’s ambitions through a general equilibrium of power...
Continue reading → Tags : diary rambling
If you are not living under a cave, you probably have already heard about carcinogens. News is often awash with headlines alerting perils of carcinogens. In a nutshell, these are substances that have the potential to cause cancer. Not all carcinogens cause cancer. Not all cancer is caused by carcinogens. Cancer is a complicated group of diseases. Of course, it’s not my forte to expound on the subject of cancer. However, we should try to understand how carcinogens are identified and what we should do to protect ourselves.
Cancer is pathological mitosis. The cells go bonkers where they have an insatiable urge to proliferate. Carcinogens have the potential to alter the genetic material of the cell. This genetic mutation sometimes can develop into cancer...
Continue reading → Tags : diary rambling carcinogen meditation
Today I tried to meditate again. I used Insight Timer app for background sound. However I think I'll just stick to Youtube as it has more varieties. I struggled for 20 minutes sitting cross-legged as my mind wandered in the labyrinth of thoughts. I guess it will take more practice to hone my skill. Have you ever wondered how monks can meditate for countless hours or days?
There’s a very famous picture of a Vietnamese monk called Thích Quảng Đức. He was protesting against the persecution of Buddhist. He self-immolated himself without making any fuss...
Continue reading → Tags : diary rambling
Did you remember we watched The Time Machine movie together? The protagonist loses his fiancée when a mugger kills her. He then builds a time machine to travel back in time to save her. Of course multiple movies have been made romanticizing the concept of time machine.
I am not sure if the laws of physics allow time travel. There’s no scientific consensus if time travel is possible in theory. Even if it was possible in theory, it might take aeons before humans could master this concept. However there’s one time machine you see everyday...
Continue reading → Tags : diary rambling
Today the sleep was better. Yesterday I was sleep deprived. Hunger is the best ingredient to make any food delicious. Likewise a sound sleep is like a `manna from heaven` for me.
I hope you are spending time honing SQL skills. I hope you are making some progress in the online course at Educative.io. There’s also another resource SQLZoo that has some fun exercise that you can explore. Next week we can take a SQL quiz together to see how well we fare against each other...
Continue reading → Tags : diary rambling
I didn't have proper sleep today. I could barely keep my eyes open. Empty stomach and a heavy mind is a disaster for sound sleep. Yesterday I was brooding too much while trying to sleep. I guess I need to filter noises in my mind. Proper sleep is the basic physiological need in Maslow's pyramid. I guess it's a blessed day not to have a insomnia.
I am beginning to practice meditation. Though I am not a religous person, I reckon meditation is a good practice to adopt from my religion. I like the babbling sound of the water while I meditate. Today I meditated for 15 minutes...
Continue reading → Tags : diary rambling
Recently I finished watching web-series Scam 1992. It's based on story of Harshad Mehta, a famous Indian stockbrocker who made fortunes in stocks. Despite his iconic success & failure, the series rekindled my interest in world of "stocks". I guess the famous dialogue "Risk Hai Toh Ishq Hai" has stuck with me.
I still consider myself a novice in stocks. There’s a no magic bullet to make money in stocks. However you can leverage scripts to reduce time to accumulate information. I’ll share one such approach in helping buying or selling stocks...
Continue reading → Tags : stocks python finance money google selenium
I am currently reading The Emperor of Maladies. This is a fascination book where Siddhartha Mukherjee not only educate its readers about cancer disease but also shares interesting tidbits. Werner Bezwoda was an infamous oncologist who fudged data about bone marrow transplant in women with metastatic breast cancer.
Before I understood anything, I have to understand what the heck was a bone marrow. I remembered vaguely from my science class in school but I guess I needed a revision...
Continue reading → Tags : pseudoscience cancer breast cancer bone marrow
Poetry is a great dependency management tool in python. It's better than managing a flat file like `requirements.txt`. There are also other great tools like pipenv. However I found poetry much simpler in resolving dependencies.
Recently poetry has been crashing on my Windows machine. However, I have not encountered this issue in other platform like Linux. Folks who are unfamiliar with poetry, below is a quick refresher...
Continue reading → Tags : windows python poetry bug
Dynamodb is a great NoSQL service by AWS. One of the most common use case is to export data to s3. There are multiple ways to export data to s3. For this tutorial we will leverage lambda function to achieve our goal.
First, let us review our use case. Our lambda function will read the entire dynamodb table. It will then export the data in JSON to s3...
Continue reading → Tags : aws lambda function dynamodb s3
I recently came across a Youtube video of Genelia Deshmukh, famous Indian actress, promoting homeopathic products. Along with her husband, they have invested in a startup called Welcome Cure. Science has repeatedly dismissed homepathy as quakery or at best placebo, but that has not deter government of India to fund & research homeopathy under AYUSH ministry.
As a kid I usually heard about two types of medicine. One was allopathy which is a pejorative term for modern science. It was always blamed for side effects. “Only if you are really sick”, my uncle used to say, “should you take allopathy”...
Continue reading → Tags : pseudoscience homeopathy ayurveda india
This is my Part 1 of the review of Carl Sagan's book, Demon-Haunted World. This is more of my commentary rather than a review of the book.
I have begun to realize how many posts on Facebook, Whatsapp, etc contains pseudoscience & misinformation. Few posts are easy to debunk. Magic water curing cancer is a no-brainer. However other posts are too meticulous to debunk. I thought it might be fruitful for me as a layman to learn critical & skeptical thinking from a famous astrophysicist, Carl Sagan. ..
Continue reading → Tags : pseudoscience carl sagan books review cfc religion
I was looking to write a scala script to fetch large data from Oracle database. I was earlier using the Alteryx software to fetch data (around 1 million rows) from oracle which took around 7 minutes. Licensed softwares like Alteryx or Informatica, etc are great, but I was looking for a free solution.
We need ojdbc6.jar to connect to the Oracle 12 c database. We will create a Scala script to fetch data from the oracle database & save it to the output file (CSV format)...
Continue reading → Tags : jdbc scala oracle database
It feels great to sleep at night. I have a small but a cozy room. It’s not lavish or splending. It doesn’t even hoard much furniture. However it’s as peaceful as it can get.
I wonder about those unfortunate people who couldn’t sleep at night. Some of them are stuck in war-torn countries. Around 150 million people are homeless in the world. Astonishing 1.6 billion people don’t have proper housing. That’s 20 percent of the entire human population...
Continue reading → Tags : sleep rambling human rights
Jobs failed! Screamed an automatic failure alert in email inbox. Existing python scripts were failing in the server which fetched data from Oracle database. I wondered if the credentials had changed.
After few emails back and forth with the Support team, I discoverd that the server had been upgraded with Kerberos authentication. I have to modify my scripts to support kerberos authentication. I have to dig up more to understand more about kerberos...
Continue reading → Tags : kerberos projects python docker oracle database
India is currently witnessing multiple protests against the Citizenship Amendment Act (CAA) passed by the BJP (the ruling party of India). In a nutshell it fast tracks citizenship to few religiously persecuted refugees like Hindu, Sikh, Jain, Buddhist, Christian and Parsi from neighbouring countries.
Some argue this act brazenly violates secular structure of India by explicitly inserting religious clause in the constitution...
Continue reading → Tags : faiz india urdu bjp nationalism caa nrc npr
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)..
Continue reading → Tags : graph java code
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…..
Continue reading → Tags : programming interview merge sort sort java code
When I was a kid, I was perturbed at the outbreaks of new diseases. There was no Swine Flue before twenty first century or HIV before tenth century. Why nature was hell-bent in pulling diseases out of a hat everytime humans make progress in science?
Naively I belived that new diseases were nature’s way of pushing against human’s advancement in science. Nature had to ensure that human’s dont overflow the planet. I belived in Rita (Sanskrit ṛta ), a cosmic order of the universe. The wheel of dharma(duty) & karma (accumulated effects of good and bad actions) somehow illusioned to maintain harmony in the world. But evolution shattered my perception of reality...
Continue reading → Tags : biology evolution antibiotics
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. ..
Continue reading → Tags : programming leetcode code
I wanted to decode an old debate 1 that I saw on ndtv. It was about a controversy erupted by the comments of a junior Indian education minister, Satyapal Singh. He is India's Minister of State for Human Resource Development. He had claimed that evolution is "scientifically wrong" because he never "saw an ape turning into human being".
How does he claim evolution is “scientifically wrong”? Does the said minister have a degree in biology or have published a paper that can be peer reviewed? On the contrary, he had a career of Police Commisioner of Mumbai...
Continue reading → Tags : pseudoscience evolution india ndtv news debate
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
..Continue reading → Tags : programming leetcode code
I might slip into a cesspool of hate in criticizing India’s most successful movie, Baahubali 2: The Conclusion. One of my Telugu colleague eyes beamed with pride when she told me how she watched first day first show & how this movie has propelled Telugu movies in the same league of Hollywood.
People in India often put actors and politicians in pedestal with overwhelming emotions which is why it is sometimes difficult to have bonafide criticism of more than real life people like Rajinikanth in Tamil Nadu or Salman Khan in UP or Bihar...
Continue reading → Tags : baahubali movies
Recently, my roommate, had his job contract terminated. He found a new job in another city which meant I had to hunt for a new roommate. So I quickly posted an ad on Sulekha, a popular website in USA among Indians.
A month ago I had stumbled upon an old friend in a private birthday bash. He was raving about a rent scam. More than thousands of dollars were siphoned off his account. Barring some sympathy, I paid little heed to his story. Little did I know I would almost fell for a similar scam...
Continue reading → Tags : rent scam
The sun’s rays had already crept through my window & drenched my room with light. Sleep taste sweetest when you resist it. It is but with a heavy heart that I relinquish my sleep & pull myself together.
But not today! It was a weekend that brought me few more drops of honey as I extended my sleep while a statue of abstemious Buddha, which I recently bought, wandered at the petty cumberworld outgrowing in both time & stupidity.
..Continue reading → Tags : lazy meditation
On a brisk day, I was carpooling with my manager. Amidst the roaring traffic, was the familiar melodious voice on the radio. We have grown accustomed to the RJ who played songs that was music to our ears. As my manager revved up the engine, with the occasional drip in audio of the AM, often we broke into conversation.
Amartya Sen in his book, The Argumentative Indian, has argued the Indians are inherently loquacious. True to the argumentative traditions, our conversation percolated through the porous soil of sports into the sedimentary rocks of politics while amassing lump of Bollywood, music, economics, etc along the way. While an old classic Bollywood song played on the radio and I hummed along, dragging our conversation to halt. I gazed out of the window, many sign posts passed by, most of them visibly crestfallen like me...
Continue reading → Tags : india pakistan cow vigilantism
It was just another day in Bangalore. I caught the bus from the Kormangala bus depot. Amid exhausting heat & nudging elbows, I somehow managed to grab a seat in the bus. Securing a seat in the Indian bus during peak time is considered a fortune. This often attracts resentful eyes. However my Indian genes have made me immune to both pani puri & judgment.
If you are lucky, you could get a window seat. This saves you from claustrophobia of the overcrowded isles. And today was my lucky day. I happily slumped down into my seat and peeped out of my window catching some glimpse of just another life on just another Indian road...
Continue reading → Tags : story india fiction bangalore sci-fi
Browsers have made browsing insanely easy. Toolbar fetches webpage magically. However, under the hood, lots of requests are exchanged. These requests are based on REST architecture.
What is REST? REST is REpresentational State Transfer. Loosely speaking it defines how resources are exchanged based on item of request. Two most common HTTP Request Methods are POST and GET. Using tshark, we can see the headers exchange as you browse the web...
Continue reading → Tags : tshark rest http get post
I finally divorced Windows soon after I fell in love with Linux. Ubuntu was my first love. I met her on Distrowatch. But she spoke no English. So I spent hours gawking at her sleaky terminal trying to learn her language, bash.
Soon I flirted with others; Mint came but reminded me of my ex, Fedora had a different yum, BSD couldn’t agree on my license, Debian was old schooled. Few months ago, I discovered grey hair on my head and decided to settle down. So I started looking for someone who was simple yet was elegant. Little did I know that I would stumble upon Arch Linux..
Continue reading → Tags : arch linux install
Any deterministic general sorting algorithm has average case time complexity @L \Omega(n\log{}n) @L . However, certain sorting algorithm can run faster in @L O(n) @L 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...
Continue reading → Tags : code lsd radix sort sorting
Imagine a sunset, with a tired sun sinking over a meadow. The chirping of birds steals your attention as they return to their homes. And while the sun disappears, you sink back and relish your sourrounding.
Well the sunset is beautiful because it’s obvious to your eyes. Similarly programming is beautiful for those who enjoy it. Below is the poem which which eulogises lisp programming language, but it may be bland for those who have no experience with lisp...
Continue reading → Tags : programming general
"If you've got nothing to hide, you've got nothing to fear". This is the most common retort used by governments to espouse Mass surveillance. They do it in the pretext of security. But even if you're not a fugitive, you have the right to protect your privacy.
Surveillance, for example, can inhibit such lawful activities as free speech, free association, and other First Amendment rights essential for democracy.Edward Snowden leaked the largest infamous clandestine mass surveillance by the NSA and GCHQ called PRISM (surveillance program). ..
Continue reading → Tags : privacy surveillance snooping
"India’s Daughter”, a documentary on Gang rape of 2012 has been officially banned. The Indian government went all gun to arrest the release of the documentary in India & abroad. BBC, Google, Youtube have all been sent legal notices to comply with the government’s diktat. Congratulations! We have shown the world that we will silence anything that will make us uncomfortable.
Leslee Udwin, the maker of the documentary, has flown out of India citing her security. In an interview to BBC, she said, “But I’m not muzzled. Nor will I be muzzled”. India’s Home Minister, Rajnath Singh, was furious & sought report from Tihar’s jail authorities on how the Nirbhaya’s rape accused had given a controversial interview to BBC. “This is an international conspiracy to defame India. We will see how the film can be stopped abroad too”, said parliamentary affairs minister M. Venkaiah Naidu...
Continue reading → Tags : bbc india ban
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...
Continue reading → Tags : code cryptography cipher monoalphabetic
Often we meet,
Avoiding prying eyes secretly,
In between stretches a velvet sky,
Only gulf in between us apparently.
High tides doth comes,
As she tries approaching me,
And sweeps the earth below,
Posing as the one, only she could be.
..
Continue reading → Tags : poetry romance moon
I was lying around on a secluded meadow. Under the open sky I gazed at the clouds scudding by. Suddenly it seemed that I was drifting away. A scathing sound began to wreak the whole place. And the mischievous alarm pulled me out of my dreams.
After few seconds, the world came back to me. I glanced out of the window to catch any trace of light. The day had dawned with the sun steadily climbing up the sky. Few stars probably were lost and still wandered around. I flung open the door of my room and stood before the balcony...
Continue reading → Tags : god religion science
I walked miles on my feet and hope,
against all weather, people and slope,
But after some distance I could not keep,
enough pace as the way was steep.
I was already late not by months but years,
still I dragged my feet amidst all fears,
at night when the moon swept the tides away,
I dreamt of my past till sleep made me her prey...
Continue reading → Tags : poetry happiness
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...
Continue reading → Tags : emacs editor code
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...
Continue reading → Tags : vi vim editor code
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...
Continue reading → Tags : hacking hackers code
As I lay on my cosy bed,
a hanging moon did my curtains lit,
under my pillow sank my weary head,
and slumber weaved its sleepy knit.
The clock ticked and ticked away,
I climbed mountains and travelled like a bullet,
no laws of physics or Michael Faraday,
only in dreams can everyone shine like a starlet...
Continue reading → Tags : poetry sleep
The Debian claimed to be the Universal Operating System. Impressed by the stability and the community, I decided to switch to Debian. Earlier I used Fedora which handled all the hassles for me. Unlike Fedora, I had manually configure it to connect to the internet. But I soon realized it was not as difficult as it earlier seemed to be.
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...
Continue reading → Tags : debian huawei usb modem code
After a ruckus the government agreed to roll back the proposed decision to increase FDI in retail sector. This could have paved way for the behemoth giants like Walmart to enter India. Indian Inc. was largely disappointed with the lack of much needed retail reform while the opposition parties including the local shopkeeper rejoiced over the fear of Walmart.
My lack of education in economics convinced me of my inability to form an opinion on this matter. But as a concerned citizen , I tried to understand the repercussion of such an important law debated in the parliament...
Continue reading → Tags : Walmart FDI