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Blog
This is where I share stuff that I find useful, interesting, beautiful or thought provoking on a multitude of topics.
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A Prime Sum Circle
mathematics
puzzles
And related puzzles solved using Graph Theory
Feb 19, 2024
Running Total of a Die
probability
puzzles
Solved using two different approaches.
Feb 7, 2024
Some Off Square
probability
puzzles
Solved using two different approaches.
Feb 7, 2024
Can you find the luckiest coin?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 18, 2022
En Garde! Can You Win The Fencing Relay?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Dec 10, 2021
Can You Slice The Ice?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Dec 3, 2021
Can you stick it to the genie?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Nov 19, 2021
Traveling Salesman Problem
branch and bound
optimization
mathematical programming
Solution using Branch and Bound.
Nov 8, 2021
How Many Friends Are On The Riddler Social Network?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Nov 5, 2021
Langford problem
integer programming
puzzles
Three different solutions.
Nov 1, 2021
Can You Survive Squid Game?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Oct 29, 2021
Who Betrayed Dune’s Duke Leto?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Oct 22, 2021
Flowfree
integer programming
puzzles
Solution using constraint programming.
Oct 10, 2021
Riddle of the pilgrims
integer programming
puzzles
Solution using integer programming.
Oct 9, 2021
Graphs and Integer Programming
integer programming
mathematical programming
Optimization using linear models.
Oct 2, 2021
Can You Climb Your Way To Victory?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Sep 24, 2021
Modeling using Integer Programming
integer programming
mathematical programming
Optimization using linear models.
Sep 21, 2021
Modeling using Linear Programming
linear programming
mathematical programming
Optimization using linear models.
Sep 20, 2021
Can You Bake The Radish Pie?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Sep 17, 2021
Can You Get The Paper Cut?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Sep 10, 2021
On camels and straws
probability
mathematics
A famous puzzle about probability and expectation involving sum of uniform random variables.
Aug 27, 2021
Can You Draft A Riddler Fantasy Football Dream Team?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Aug 27, 2021
Can you catch the cricket?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Aug 20, 2021
Are You Clever Enough?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Aug 13, 2021
Evolutionary Computation
mathematics
optimization
metaheuristics
The power of the technique illustrated with a couple of examples.
Aug 10, 2021
Simulated Annealing
mathematics
optimization
metaheuristics
The power of the technique illustrated with a couple of examples.
Aug 5, 2021
Will Riddler Nation Win Gold In Archery?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jul 30, 2021
Can You Hop Across The Chess Board?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jul 23, 2021
Can You Win The Penalty Shootout?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jul 16, 2021
Problem 1325 - A surprising polygon formula
mathematics
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
\(n\)
. …
Jul 9, 2021
Can You Solve This Astronomical Enigma?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jul 9, 2021
Can You Decipher The Secret Message?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jun 4, 2021
Can You Crack The Case Of The Crystal Key?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
May 28, 2021
No Isosceles Triangles For You!
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
May 21, 2021
Can You Systematically Solve A Friday Crossword?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 30, 2021
Can You Cut The Perfect Pancake?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 23, 2021
Can You Crack The Case Of The Crescent Moon?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 16, 2021
Happy Birthday Sharada!
julia
PenPlots
birthday
Sharada
life
A geeky gift for my beautiful wife on her birthday.
Apr 14, 2021
Who owns the fish?
Z3
puzzles
Using the fantastic Z3 for fun.
Apr 9, 2021
Can You Navigate The One-Way Streets?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 9, 2021
Can You Find An Extra Perfect Square?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Mar 19, 2021
Unusual Crossword
mathematics
An unusual crossword based on the first 30 digits of pi.
Mar 14, 2021
Can You Bake The Biggest π?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Mar 13, 2021
Can You Bat .299 In 299 Games?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Mar 6, 2021
25 Tech Trends in Practice
Most of the trends described in this
book
are about
data
.
Mar 1, 2021
How Many Ways Can You Build A Staircase?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 27, 2021
Can You Win Riddler Jenga?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 19, 2021
Can You Cross Like A Boss?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 13, 2021
Can You Randomly Move The Tower?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 6, 2021
Little Cubes
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 30, 2021
Can You Skillfully Ski The Slopes?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 23, 2021
Can You Hunt For The Mysterious Numbers?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 16, 2021
An Archery problem
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Jan 9, 2021
Hamiltonian Cycles
problem solving
graph theory
A couple of hamiltonian cycles that I stumbled upon.
Dec 31, 2020
Net Promoter Score
business
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…
Dec 25, 2020
Expected distance of a random point from the centre of a regular polygon with circumradius one
mathematics
probability
Calculating expectation analytically and computationally.
Dec 18, 2020
Knights on a chess board
markov chains
probability
mathematics
The power and beauty of Markov Chains.
Nov 19, 2020
Fixed Income with Python - 1
finance
python
fixed income
quantlib
Basics of fixed income instruments.
Oct 26, 2020
Investment Management with Python - 3
finance
python
investment management
Portfolio Optimization and Efficient Frontier
Oct 26, 2020
Investment Management with Python - 2
finance
python
investment management
Beyond the Gaussian case:Extreme risk estimates
Oct 25, 2020
Investment Management with Python - 1
finance
python
investment management
Fundamentals of Return and Risk
Oct 24, 2020
Can You Reach The Summit First?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Sep 16, 2020
Ikigai
business
AI
The ten rules.
Sep 14, 2020
Breaking a slide rule into four pieces
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Aug 14, 2020
Basics of network science with Networkx - 2
python
graph theory
data science
Second instalment in the exploratory data analysis of graphs
Jul 25, 2020
Basics of network science with Networkx - 1
python
graph theory
data science
First instalment in the exploratory data analysis of graphs
Jul 23, 2020
Bandit Algorithms For Website Optimization
algorithms
machine learning
bandit algorithms
python
This is my summary of the book - Bandit Algorithms for Website Optimization by John Myles White
Jul 21, 2020
Generalized problem of counterfeit coins
discrete mathematics
A famous puzzle about identifying counterfeit coins using the least number of weighings.
Jul 6, 2020
Counting triangles in a graph
linear algebra
graph theory
Various techniques for counting and listing triangles in a graph.
Jul 5, 2020
Centered Pentagonal Number
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jul 3, 2020
Can you flip the magic coin?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jun 19, 2020
142857 - A remarkable number
mathematics
number theory
recreational
Surprising properties of cyclic numbers.
Jun 17, 2020
Inversion - A beautiful idea from Geometry
mathematics
geometry
There are
\(3\)
semi circles and infinite circles in this figure
Jun 8, 2020
Solving Squares Sudoku using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
May 23, 2020
Solving 3-In-A-Row using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
May 7, 2020
Can You Tell When The Snow Started?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 3, 2020
Same number on all the dies
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Mar 27, 2020
Random Tic Tac Toe
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Mar 6, 2020
Should The Grizzly Bear Eat The Salmon?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Mar 5, 2020
Solving Kakuro using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
Mar 2, 2020
Solving Calcudoku using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
Mar 1, 2020
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…
Feb 28, 2020
Can You Get A Haircut Already?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Feb 28, 2020
Islamic Geometric Patterns
art
In this post, we will explore a computational approach that can produce beautiful patterns like the one below
Jan 28, 2020
Delirious Ducks
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 17, 2020
Can You Find A Number Worth Its Weight In Letters?“
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 10, 2020
Can You Solve The Vexing Vexillology?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 3, 2020
Can You Find A Matching Pair Of Socks?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Dec 20, 2019
SQL Practice Problems - Advanced
SQL
Solutions to advanced problems from the book - SQL Practice Problems
Dec 9, 2019
SQL Practice Problems - Basic
SQL
Solutions to basic problems from the book - SQL Practice Problems.
Dec 8, 2019
SQL Practice Problems - Intermediate
SQL
Solutions to intermediate problems in the book - SQL Practice Problems.
Dec 8, 2019
Solving a Cryptarithmetic puzzle using Z3
Replace “P” with a prime integer below to ensure that the multiplication is valid
Dec 3, 2019
How Low Can You Roll?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Nov 15, 2019
How Many Ways Can You Raid The Candy Shop?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Nov 8, 2019
Solving Kakurasu using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
Oct 29, 2019
Solving Skyscrapers using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
Oct 28, 2019
Solving Numbrix using Z3
Z3
puzzles
Using the fantastic Z3 for fun.
Oct 25, 2019
Loading IMDB data into SQLite in 200 lines of Python
data management
python
You will be surprised how incredibly useful and powerful SQLite is.
Oct 6, 2019
Who Wants To Be A Riddler Millionaire?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Oct 4, 2019
Problems by Ramanujan
mathematics
Submitted to the Journal of the Indian Mathematical Society (JIMS).
Aug 15, 2019
Points on a circle
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 19, 2019
What Are The Odds You’d Already Have My Number?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Nov 9, 2018
When Will The Arithmetic Anarchists Attack?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 6, 2018
Can You Shuffle Numbers?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Mar 23, 2018
Can You Rescue The Paratroopers?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 23, 2018
Probability and vitamin pills
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 2, 2018
Solving Ostomachion using Z3
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 26, 2018
Where Will The Seven Dwarfs Sleep Tonight?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 5, 2018
Help Us Find These Missing Pieces
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Nov 10, 2017
Can you help a frogger out?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Nov 3, 2017
How Do You Like Them Rectangles?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Sep 22, 2017
Will You Be A Ghostbuster Or A World Destroyer?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Sep 15, 2017
Work A Shift In The Riddler Gift Shop
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Aug 25, 2017
Who Steals The Most In A Town Full Of Thieves?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jun 30, 2017
My Dad’s ‘mystery cold’
life
My Sherlock Holmes moment.
Jun 15, 2017
Can You Time The Stoplight Just Right?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 20, 2017
How Long Will It Take To Blow Out The Birthday Candles?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Jan 13, 2017
Can You Slay The Puzzle Of The Monsters’ Gems?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
May 20, 2016
Can You Solve This Elevator Button Puzzle?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
May 6, 2016
The Puzzle Of Misanthropic Neighbors?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 22, 2016
You Have $1 Billion To Win A Space Race. Go.
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Apr 15, 2016
Should You Pay $250 To Play This Casino Game?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Mar 25, 2016
Should You Shoot Free Throws Underhand?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Mar 11, 2016
Will Someone Be Sitting In Your Seat On The Plane?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Feb 19, 2016
How Many Cars Will Get Stuck In Traffic?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Feb 5, 2016
Night Falls. A Storm Rolls In. Can You Cross The River?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Jan 22, 2016
Real SQL Queries - 50 Challenges
SQL
Challenging problems from the book - Real SQL Queries - 50 Challenges
Jan 22, 2016
Will The Neurotic Basketball Player Make His Next Free Throw?
Riddler
mathematics
A FiveThirtyEight Riddler puzzle.
Jan 15, 2016
How Long Will Your Smartphone Distract You From Family Dinner?
mathematics
Riddler
A FiveThirtyEight Riddler puzzle.
Dec 22, 2015
Interesting Questions
life
A collection of intriguing questions from multiple sources.
Nov 24, 2014
Edwise - exploiting the long tail of education
business
A business that leverages the long tail.
Sep 25, 2006
The Paint Industry
business
The industry is more complicated than you think it is.
Apr 6, 2006
Payment cards at malls
The logic behind why some malls have their own cards for payment.
Feb 9, 2006
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