Blog | Vamshi Jandhyala

A Prime Sum Circle

Arrange the numbers \(1, 2, 3, ..., 20\) in a circle so that the sum of any two neighboring numbers is prime. The problem is known as the “Prime Circle Problem” and is due…

Can you find the luckiest coin?

A FiveThirtyEight Riddler puzzle.

En Garde! Can You Win The Fencing Relay?

A FiveThirtyEight Riddler puzzle.

Can You Slice The Ice?

A FiveThirtyEight Riddler puzzle.

Can you stick it to the genie?

A FiveThirtyEight Riddler puzzle.

How Many Friends Are On The Riddler Social Network?

A FiveThirtyEight Riddler puzzle.

Can You Survive Squid Game?

A FiveThirtyEight Riddler puzzle.

Who Betrayed Dune’s Duke Leto?

A FiveThirtyEight Riddler puzzle.

Can You Climb Your Way To Victory?

A FiveThirtyEight Riddler puzzle.

Can You Bake The Radish Pie?

A FiveThirtyEight Riddler puzzle.

Can You Get The Paper Cut?

A FiveThirtyEight Riddler puzzle.

On camels and straws

A famous puzzle about probability and expectation involving sum of uniform random variables.

Can You Draft A Riddler Fantasy Football Dream Team?

A FiveThirtyEight Riddler puzzle.

Can you catch the cricket?

A FiveThirtyEight Riddler puzzle.

Are You Clever Enough?

A FiveThirtyEight Riddler puzzle.

Evolutionary Computation

The power of the technique illustrated with a couple of examples.

Simulated Annealing

The power of the technique illustrated with a couple of examples.

Will Riddler Nation Win Gold In Archery?

A FiveThirtyEight Riddler puzzle.

Can You Hop Across The Chess Board?

A FiveThirtyEight Riddler puzzle.

Can You Win The Penalty Shootout?

A FiveThirtyEight Riddler puzzle.

Problem 1325 - A surprising polygon formula

For a regular polygon with \(n\) sides (\(n\) even) and side-length \(2\), prove that the sum of the squares of the segments along a vertical line as in the diagram is \(n\). …

Can You Solve This Astronomical Enigma?

A FiveThirtyEight Riddler puzzle.

Can You Decipher The Secret Message?

A FiveThirtyEight Riddler puzzle.

Can You Crack The Case Of The Crystal Key?

A FiveThirtyEight Riddler puzzle.

No Isosceles Triangles For You!

A FiveThirtyEight Riddler puzzle.

Can You Systematically Solve A Friday Crossword?

A FiveThirtyEight Riddler puzzle.

Can You Cut The Perfect Pancake?

A FiveThirtyEight Riddler puzzle.

Can You Crack The Case Of The Crescent Moon?

A FiveThirtyEight Riddler puzzle.

Happy Birthday Sharada!

A geeky gift for my beautiful wife on her birthday.

Can You Navigate The One-Way Streets?

A FiveThirtyEight Riddler puzzle.

Can You Find An Extra Perfect Square?

A FiveThirtyEight Riddler puzzle.

Unusual Crossword

An unusual crossword based on the first 30 digits of pi.

Can You Bake The Biggest π?

A FiveThirtyEight Riddler puzzle.

Can You Bat .299 In 299 Games?

A FiveThirtyEight Riddler puzzle.

25 Tech Trends in Practice

Most of the trends described in this book are about data.

How Many Ways Can You Build A Staircase?

A FiveThirtyEight Riddler puzzle.

Can You Win Riddler Jenga?

A FiveThirtyEight Riddler puzzle.

Can You Cross Like A Boss?

A FiveThirtyEight Riddler puzzle.

Can You Randomly Move The Tower?

A FiveThirtyEight Riddler puzzle.

Little Cubes

A FiveThirtyEight Riddler puzzle.

Can You Skillfully Ski The Slopes?

A FiveThirtyEight Riddler puzzle.

Can You Hunt For The Mysterious Numbers?

A FiveThirtyEight Riddler puzzle.

An Archery problem

A FiveThirtyEight Riddler puzzle.

Hamiltonian Cycles

problem solving

A couple of hamiltonian cycles that I stumbled upon.

Net Promoter Score

In 1996, Fred Reichheld published a best-selling—book called The Loyalty Effect, in which he proposed a model for business success with customers. The book explicitly…

Expected distance of a random point from the centre of a regular polygon with circumradius one

Calculating expectation analytically and computationally.

Knights on a chess board

The power and beauty of Markov Chains.

Fixed Income with Python - 1

Basics of fixed income instruments.

Investment Management with Python - 3

investment management

Portfolio Optimization and Efficient Frontier

Investment Management with Python - 2

investment management

Beyond the Gaussian case:Extreme risk estimates

Investment Management with Python - 1

investment management

Fundamentals of Return and Risk

Can You Reach The Summit First?

A FiveThirtyEight Riddler puzzle.

Ikigai

Breaking a slide rule into four pieces

A FiveThirtyEight Riddler puzzle.

Basics of network science with Networkx - 2

Second instalment in the exploratory data analysis of graphs

Basics of network science with Networkx - 1

First instalment in the exploratory data analysis of graphs

Bandit Algorithms For Website Optimization

machine learning

bandit algorithms

This is my summary of the book - Bandit Algorithms for Website Optimization by John Myles White

Centered Pentagonal Number

A FiveThirtyEight Riddler puzzle.

Can you flip the magic coin?

A FiveThirtyEight Riddler puzzle.

142857 - A remarkable number

Surprising properties of cyclic numbers.

Inversion - A beautiful idea from Geometry

There are \(3\) semi circles and infinite circles in this figure

Can You Tell When The Snow Started?

A FiveThirtyEight Riddler puzzle.

Same number on all the dies

A FiveThirtyEight Riddler puzzle.

Random Tic Tac Toe

A FiveThirtyEight Riddler puzzle.

Should The Grizzly Bear Eat The Salmon?

A FiveThirtyEight Riddler puzzle.

Connected paths in a \(2 \times n\) grid

Consider a 2x12 rectangle with dotted lines marking the 24 squares. How many sets R are there such that R is connected, R is obtained by cutting on the dotted lines, and R…

Can You Get A Haircut Already?

A FiveThirtyEight Riddler puzzle.

Islamic Geometric Patterns

In this post, we will explore a computational approach that can produce beautiful patterns like the one below

Delirious Ducks

A FiveThirtyEight Riddler puzzle.

Can You Find A Number Worth Its Weight In Letters?“

A FiveThirtyEight Riddler puzzle.

Can You Solve The Vexing Vexillology?

A FiveThirtyEight Riddler puzzle.

Can You Find A Matching Pair Of Socks?

A FiveThirtyEight Riddler puzzle.

SQL Practice Problems - Advanced

Solutions to advanced problems from the book - SQL Practice Problems

SQL Practice Problems - Basic

Solutions to basic problems from the book - SQL Practice Problems.

SQL Practice Problems - Intermediate

Solutions to intermediate problems in the book - SQL Practice Problems.

How Low Can You Roll?

A FiveThirtyEight Riddler puzzle.

How Many Ways Can You Raid The Candy Shop?

A FiveThirtyEight Riddler puzzle.

Loading IMDB data into SQLite in 200 lines of Python

data management

You will be surprised how incredibly useful and powerful SQLite is.

Who Wants To Be A Riddler Millionaire?

A FiveThirtyEight Riddler puzzle.

Problems by Ramanujan

Submitted to the Journal of the Indian Mathematical Society (JIMS).

Points on a circle

A FiveThirtyEight Riddler puzzle.

What Are The Odds You’d Already Have My Number?

A FiveThirtyEight Riddler puzzle.

When Will The Arithmetic Anarchists Attack?

A FiveThirtyEight Riddler puzzle.

Can You Shuffle Numbers?

A FiveThirtyEight Riddler puzzle.

Can You Rescue The Paratroopers?

A FiveThirtyEight Riddler puzzle.

Probability and vitamin pills

A FiveThirtyEight Riddler puzzle.

Solving Ostomachion using Z3

A FiveThirtyEight Riddler puzzle.

Where Will The Seven Dwarfs Sleep Tonight?

A FiveThirtyEight Riddler puzzle.

Help Us Find These Missing Pieces

A FiveThirtyEight Riddler puzzle.

Can you help a frogger out?

A FiveThirtyEight Riddler puzzle.

How Do You Like Them Rectangles?

A FiveThirtyEight Riddler puzzle.

Will You Be A Ghostbuster Or A World Destroyer?

A FiveThirtyEight Riddler puzzle.

Work A Shift In The Riddler Gift Shop

A FiveThirtyEight Riddler puzzle.

Who Steals The Most In A Town Full Of Thieves?

A FiveThirtyEight Riddler puzzle.

My Dad’s ‘mystery cold’

My Sherlock Holmes moment.

Can You Time The Stoplight Just Right?

A FiveThirtyEight Riddler puzzle.

How Long Will It Take To Blow Out The Birthday Candles?

A FiveThirtyEight Riddler puzzle.

Can You Slay The Puzzle Of The Monsters’ Gems?

A FiveThirtyEight Riddler puzzle.

Can You Solve This Elevator Button Puzzle?

A FiveThirtyEight Riddler puzzle.

The Puzzle Of Misanthropic Neighbors?

A FiveThirtyEight Riddler puzzle.

You Have $1 Billion To Win A Space Race. Go.

A FiveThirtyEight Riddler puzzle.

Should You Pay $250 To Play This Casino Game?

A FiveThirtyEight Riddler puzzle.

Should You Shoot Free Throws Underhand?

A FiveThirtyEight Riddler puzzle.

Will Someone Be Sitting In Your Seat On The Plane?

A FiveThirtyEight Riddler puzzle.

How Many Cars Will Get Stuck In Traffic?

A FiveThirtyEight Riddler puzzle.

Night Falls. A Storm Rolls In. Can You Cross The River?

A FiveThirtyEight Riddler puzzle.

Real SQL Queries - 50 Challenges

Challenging problems from the book - Real SQL Queries - 50 Challenges

Will The Neurotic Basketball Player Make His Next Free Throw?

A FiveThirtyEight Riddler puzzle.

How Long Will Your Smartphone Distract You From Family Dinner?

A FiveThirtyEight Riddler puzzle.

Interesting Questions

A collection of intriguing questions from multiple sources.

Edwise - exploiting the long tail of education

A business that leverages the long tail.

The Paint Industry

The industry is more complicated than you think it is.

Payment cards at malls

The other day me and my friend went to watch the movie ‘Rang De Basanti’ at the Inox theatre at The Forum, Calcutta.The evening show was at 5:25pm and we reached the place…