RogerBW's Blog

I’ve been doing the Weekly Challenges. The latest involved various sorts of numerical search. (Note that this is open until 23 January 2022.)

I’ve been doing the Weekly Challenges. The latest involved prime searches and pentagonal numbers. (Note that this is open until 16 January 2022.)

I’ve been doing the Weekly Challenges. The latest involved prime-counting and fraction trees. (Note that this is open until 9 January 2022.)

I’ve been doing the Weekly Challenges. The latest involved vector multiplication and a recently-invented data structure. (Note that this is open until 2 January 2022.)

I’ve been doing the Weekly Challenges. The latest involved some interesting mathematical sequences. (Note that this is open until 26 December 2021.)

I’ve been doing the Weekly Challenges. The latest involved counting divisors and another joke sort. (Note that this is open until 19 December 2021.)

I’ve been doing the Weekly Challenges. The latest involved counting divisors and another joke sort. (Note that this is open until 12 December 2021.)

I’ve been doing the Weekly Challenges. The latest involved an unusual binary encoding and indexing into a multiplication table. (Note that this is open until 5 December 2021.)

I’ve been doing the Weekly Challenges. The latest involved an unusual binary encoding and indexing into a multiplication table. (Note that this is open until 28 November 2021.)

I’ve been doing the Weekly Challenges. The latest involved date calculations and numerical decompositions. (Note that this is open until 21 November 2021.)

I’ve been doing the Weekly Challenges. The latest involved date calculations and numerical decompositions. (Note that this is open until 14 November 2021.)

I’ve been doing the Weekly Challenges. The latest involved date calculations and numeric palindromes. (Note that this is open until 7 November 2021.)

I’ve been doing the Weekly Challenges. The latest involved GCDs, powers of two, and an unusual numeric sequence. (Note that this is open until 31 October 2021.)

I’ve been doing the Weekly Challenges. The latest involved digit substrings and securities validation. (Note that this is open until 24 October 2021.)

I’ve been doing the Weekly Challenges. The latest involved pandigital numbers and multiplication tables. (Note that this is open until 17 October 2021.)

I’ve been doing the Weekly Challenges. The latest involved Smith numbers and square roots. (Note that this is open until 10 October 2021.)

I’ve been doing the Weekly Challenges. The latest involved date calculations and inner joins. (Note that this is open until 3 October 2021.)

I’ve been doing the Weekly Challenges. The latest involved splitting arrays and strings. (Note that this is open until 26 September 2021.)

I’ve been doing the Weekly Challenges. The latest involved more binary trees and linked lists. (Note that this is open until 19 September 2021.)

I’ve been doing the Weekly Challenges. The latest involved more binary trees and linked lists. (Note that this is open until 12 September 2021.)

I’ve been doing the Weekly Challenges. The latest involved finding submatrices and counting trains. (Note that this is open until 5 September 2021.)

I’ve been doing the Weekly Challenges. The latest involved set intersections and merging intervals. (Note that this is open until 29 August 2021.)

I’ve been doing the Weekly Challenges. The latest involved numbers excluding 1, and Minesweeper. (Note that this is open until 22 August 2021.)

I’ve been doing the Weekly Challenges. The latest involved Pythagorean triples and binary trees. (Note that this is open until 15 August 2021.)

I’ve been doing the Weekly Challenges. The latest involved ASCII graphics and set partitioning. (Note that this is open until 8 August 2021.)

I’ve been doing the Weekly Challenges. The latest involved regular numbers and geometrical squareness testing. (Note that this is open until 1 August 2021.)

I’ve been doing the Weekly Challenges. The latest involved a progressive average and additive compositions. (Note that this is open until 25 July 2021.)

I’ve been doing the Weekly Challenges. The latest involved more binary manipulation and a traditional problem. (Note that this is open until 18 July 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved more binary manipulation and analogue clocks. (Note that this is open until 11 July 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved fake binary manipulation and an unusual number sequence. (Note that this is open until 4 July 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved binary palindromes and a restricted Knight's Tour. (Note that this is open until 27 June 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved file analysis and combinatorial explosion. (Note that this is open until 20 June 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved lots of digit splitting. (Note that this is open until 13 June 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved chained strings and number construction. (Note that this is open until 6 June 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved unconventional solutions to numerical problems. (Note that this is open until 30 May 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved finding constrained integer decompositions and more binary tree furkling. (Note that this is open until 23 May 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved path canonicalisation and numerical compositions. (Note that this is open until 16 May 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved search optimisations and word sorting. (Note that this is open until 9 May 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved transpositions. (Note that this is open until 2 May 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved another numerical sequence and permutations. (Note that this is open until 25 April 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved bad things and triangular numbers. (Note that this is open until 18 April 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved several sorts of introspection. (Note that this is open until 11 April 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved integer differences and decimal expansion. (Note that this is open until 4 April 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved fractional exponentiation and sweating with the oldies. (Note that this is open until 28 March 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved the Stern-Brocot sequence (which Dijkstra named "fusc") and a variant of Nim. (Note that this is open until 21 March 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved lots of modulus arithmetic. (Note that this is open until 14 March 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved an obscure class of number and a self-consistent string format. (Note that this is open until 7 March 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved packing an array and a standard geometry problem. (Note that this is open until 28 February 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved converting time formats and more tree traversal. (Note that this is open until 21 February 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved globbing and building sub-sequences. (Note that this is open until 14 February 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved reading tiny chunks from a file and searching a list. (Note that this is open until 7 February 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved implementing the Caesar cipher and breaking up binary strings. (Note that this is open until 31 January 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved reversing words in a string and calculating Levenshtein distance. (Note that this is open until 24 January 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved testing for palindromic numbers and building a stack class. (Note that this is open until 17 January 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved grouping anagrams and more furkling with binary trees. (Note that this is open until 10 January 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved colinear points and binary tree sums. (Note that this is open until 3 January 2021.)

I’ve been doing the Perl Weekly Challenges. The latest involved string isomorphism and interval merging. (Note that this is open until 27 December 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved breaking down numbers and following sequences. (Note that this is open until 20 December 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved base sequences and a binary multiplication system. (Note that this is open until 13 December 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved GCDs and magic squares. (Note that this is open until 6 December 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved multiplications and spirals. (Note that this is open until 29 November 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved list searches and matrices. (Note that this is open until 22 November 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved list searches and combinatorial explosions. (Note that this is open until 15 November 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved searching combinations and integer powers. (Note that this is open until 8 November 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved reversing integers and a two-dimensional search. (Note that this is open until 1 November 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved string manipulation and a numerical search. (Note that this is open until 25 October 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved common factors and string searches. (Note that this is open until 12 October 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved substrings and word frequencies. (Note that this is open until 11 October 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved missing numbers and more ranking of neighbours. (Note that this is open until 4 October 2020.)

I’ve been doing the Perl Weekly Challenges. The latest involved more bit counts and an innovative use of histograms.

I’ve been doing the Perl Weekly Challenges. The latest involved searching array values and rotating lists.

I’ve been doing the Perl Weekly Challenges. The latest involved summing Fibonacci numbers and looking through a grid for neighbours.

I’ve been doing the Perl Weekly Challenges. The latest involved summing primes and performing a word search.

I’ve been doing the Perl Weekly Challenges. The latest involved building set values of coins and finding rectangles in histograms.

I’ve been doing the Perl Weekly Challenges. The latest involved finding minima in subsets of lists.

I’ve been doing the Perl Weekly Challenges. The latest involved finding minima in subsets of lists.

I’ve been doing the Perl Weekly Challenges. The latest involved finding the trailing zeroes of a factorial and printing a range of lines from a file.

I’ve been doing the Perl Weekly Challenges. The latest involved finding peak elements and more mucking about with linked lists.

I’ve been doing the Perl Weekly Challenges. The latest involved swapping characters, and generating Gray code.

I’ve been doing the Perl Weekly Challenges. The latest involved finding numbers that looked the same inverted, and generating a very long string.

I’ve been doing the Perl Weekly Challenges. The latest involved zeroing parts of a matrix and reordering a list.

I’ve been doing the Perl Weekly Challenges. The latest involved generating combinations of numbers and expanding telephone keypad letters.

I’ve been doing the Perl Weekly Challenges. The latest involved dividing without dividing, and making a test of factors.

I’ve been doing the Perl Weekly Challenges. The latest involved generating large numbers and splitting strings into palindromes.

I’ve been doing the Perl Weekly Challenges. The latest involved searching for paths through a grid and breaking a word into tokens.

I’ve been doing the Perl Weekly Challenges. The latest involved finding the last matching word in a string and permuting a string.

I’ve been doing the Perl Weekly Challenges. The latest involved sorting email addresses and solving a variant N-queens problem.

I’ve been doing the Perl Weekly Challenges. The latest involved searching for the maximum product in a sequence, and un-munging IPv4 addresses.

I’ve been doing the Perl Weekly Challenges. The latest involved working with a form of numeric encoding, and a very arbitrary numerical problem.

I’ve been doing the Perl Weekly Challenges. The latest involved working with a linked list and determining binary differences.

I’ve been doing the Perl Weekly Challenges. The latest involved comparing version numbers and generating an arbitrary order.

I’ve been doing the Perl Weekly Challenges. The latest involved inverting a binary tree and finding unique prefixes.

I’ve been doing the Perl Weekly Challenges. The latest involved searching arrays and summing tree paths.

I’ve been doing the Perl Weekly Challenges. The latest involved flipping bits and generating zigzag permutations.

I’ve been doing the Perl Weekly Challenges. The latest involved generating permutations and checking the Collatz Conjecture.

I’ve been doing the Perl Weekly Challenges. The latest involved a basic Markov chain.

I’ve been doing the Perl Weekly Challenges. The latest involved some game theory.

I’ve been doing the Perl Weekly Challenges. The latest involved a lot of nested loops.

I’ve been doing the Perl Weekly Challenges. The latest was about merging intervals and determining noble numbers.

I’ve been doing the Perl Weekly Challenges. The latest was about searching for particular multiples of a number, and implementing a fixed-size cache.

I’ve been doing the Perl Weekly Challenges. The latest was about calculating the survivor of a stabbing game, and determining palindromic dates.

I’ve been doing the Perl Weekly Challenges. The latest was about doing Roman arithmetic and generating gapful numbers.

I’ve been doing the Perl Weekly Challenges. The latest was about recovering a corrupted message and solving an iterative problem.

I’ve been doing the Perl Weekly Challenges. The latest was about a bad encoding scheme and producing the source of a program.

I’ve been doing the Perl Weekly Challenges. The latest was about arranging numbers and arithmetical operations.

I’ve been doing the Perl Weekly Challenges. The latest was about allocating numbers to rings and generating self-descriptive numbers.

I’ve been doing the Perl Weekly Challenges. The latest was about printing in octal and detecting balanced brackets.

I’ve been doing the Perl Weekly Challenges. The latest was about generating number sequences.

I’ve been doing the Perl Weekly Challenges. The latest was about list manipulation.

I’ve been doing the Perl Weekly Challenges. Last week's was about parsing a specific file format.

I’ve been doing the Perl Weekly Challenges. Last week's was about parsing an odd date format and generating words in a Scrabble-ish manner.

I’ve been doing the Perl Weekly Challenges. Last week's was about counting weekdays and working out total daylight.

I’ve been doing the Perl Weekly Challenges. Last week's was about validating VINs and solving the knapsack problem.

I’ve been doing the Perl Weekly Challenges. Last week's was about encoding and decoding to a binary representation of Morse code.

I’ve been doing the Perl Weekly Challenges Last week’s was about demonstrating specific coding techniques.

I’ve been doing the Perl Weekly Challenges This week’s was about counting letters and generating a multiplication table.

I’ve been doing the Perl Weekly Challenges (I missed 31 because of getting ready for Essen, and didn’t have time to do this one in Perl6). This week’s was about counting entities and generating ASCII bar charts.

I've been doing the Perl Weekly Challenges. This one dealt with date calculations and exhaustive number searches.

I've been doing the Perl Weekly Challenges. This one dealt with expanding braces and calling C functions.

I've been doing the Perl Weekly Challenges. This one dealt with testing file contents and producing the current time.

I've been doing the Perl Weekly Challenges. This one dealt with finding the intersection of two lines and doing worrying things to innocent variables.

I've been doing the Perl Weekly Challenges. This one dealt with finding letters in words and the mean of circular quantities.

I've been doing the Perl Weekly Challenges. This one dealt with building long strings and the Chaocypher.

I've been doing the Perl Weekly Challenges. This one dealt with minimal programs and inverted-index text search.

I've been doing the Perl Weekly Challenges. This one dealt with difference series and prime factorisation.

I've been doing the Perl Weekly Challenges. This one dealt with sexy primes and LZW encoding.

I've been doing the Perl Weekly Challenges. This one dealt with e, and URLs again.

I've been doing the Perl Weekly Challenges. This one dealt with string splitting and amicable numbers.

I've been doing the Perl Weekly Challenges. This one dealt with months and word-wrapping.

I've been doing the Perl Weekly Challenges. This one was a couple of standard computer-science problems.

I've been doing the Perl Weekly Challenges. This one was to implement the Ackermann function and parse URLs.

I've been doing the Perl Weekly Challenges. This one was to do a fiddly numerical calculation, and to check Bitcoin addresses.

I've recently started doing the Perl Weekly Challenges. This one was to hunt primes and do "Vigenère" enciphering.

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