My Project Euler solutions
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001-multiples-of-3-and-5.pl
002-Even-Fibonacci-numbers.pl
003-Largest-prime-factor.pl
004-Largest-palindrome-product.pl
005-Smallest-multiple.pl
006-Sum-square-difference.pl
007_010_Two-problems-concerning-primes.pl
008-Largest-product-in-a-series.pl
009-Special-Pythagorean-triplet.pl
011-Largest-product-in-grid.pl
012-Highly-divisible-triangular-number.pl
013-Large-sum.pl
014-Longest-Collatz-sequence.pl
015-Lattice-paths.pl
016-Power-digit-sum.pl
017-Number-letter-counts.pl
018-largest-sum-in-triangle.pl
019-Counting-Sundays.pl
020-Factorial-digit-sum.pl
021-Amicable-numbers.pl
022-Names-scores.pl
023-Non-abundant-sums.pl
024-Lexicographic-permutations.pl
025-1000-digit-Fibonacci-number.pl
026-Reciprocal-cycles.pl
027-Quadratic-primes.pl
028-Number-spiral-diagonals.pl
029-Distinct-powers.pl
030-Digital-fifth-powers.pl
031-Coin-sums.pl
032-Pandigital-products.pl
033-Digit-cancelling-fractions.pl
034-Digit-factorials.pl
035-Circular-primes.pl
036-Double-base-palindromes.pl
037-Truncatable-primes.pl
038-Pandigital-multiples.pl
039-Integer-right-triangles.pl
040-Champerdownes-constant.pl
041-Pandigital-prime.pl
042-Coded-triangle-numbers.pl
043-Substring-divisibility.pl
044-Pentagon-numbers.pl
045-Triangular-Pentagonal-Hexagonal.pl
046-Goldbachs-other-conjecture.pl
047-Distinct-primes-factors.pl
048-Self-powers.pl
049-Prime-permutations.pl
050-Consecutive-prime-sum.pl
051-Prime-digit-replacements.pl
052-Permuted-multiples.pl
053-Combinatoric-selections.pl
054-Poker-hands.pl
055-Lychrel-numbers.pl
056-Powerful-digit-sum.pl
057-Square-root-convergents.pl
058-Spiral-primes.pl
059-XOR-decryption.pl
060-Prime-pair-sets.pl
061-Cyclical-figurate-numbers.pl
062-Cubic-permutations.pl
063-Powerful-digit-counts.pl
064-Odd-period-square-roots.pl
065-Convergents-of-e.pl
066-Diophantine-equation.pl
067-largest-sum-in-triangle-2.pl
068-Magic-5-gon-ring.pl
069-Totient-maximum.pl
070-Totient-permutation.pl
071-Ordered-fractions.pl
072-Counting-fractions.pl
073-Counting-fractions-in-a-range.pl
074-Digit-factorial-chains.pl
075-Singular-integer-right-triangles.pl
076-Counting-summations.pl
077-Prime-summations.pl
078-Coin-partitions.pl
079-Passcode-derivation.pl
080-Square-root-digital-expansion.pl
081-Path-sum-two-ways.pl
082-Path-sum-three-ways.pl
083-Path-sum-four-ways.pl
084-Monopoly-odds.pl
085-Counting-rectangles.pl
086-Cuboid-route.pl
087-Prime-power-triples.pl
088-Product-sum-numbers.pl
089-Roman-numerals.pl
090-Cube-digit-pairs.pl
091-Right-triangles-with-integer-coordinates.pl
092-Square-digit-chains.pl
093-Arithmetic-expressions.pl
094-Almost-equilateral-triangles.pl
095-Amicable-chains.pl
096-Su-Doku.pl
097-Large-non-Mersenne-prime.pl
098-Anagramic-squares.pl
099-Largest-exponential.pl
100-picking-2-blue-disks-prob.pl
101-Optimum-polynomial.pl
102-Triangle-containment.pl
103-Special-subset-sums-optimum.pl
104-Pandigital-Fibonacci-ends.pl
105-special-subsets-testing.pl
107-Minimal-network.pl
108-Diophantine-reciprocals-1.pl
110-Diophantine-reciprocals-2.pl
111-Primes-with-runs.pl
112-Bouncy-numbers.pl
113-Non-bouncy-numbers.pl
114-Counting-block-combinations-1.pl
115-Counting-block-combinations-2.pl
116-Red-green-or-blue-tiles.pl
117-Red-green-or-blue-tiles-2.pl
118-Pandigital-prime-sets.pl
119-Digit-power-sum.pl
120-Square-remainders.pl
121-Disc-game-prize-fund.pl
123-Prime-square-remainders.pl
124-Ordered-radicals.pl
125-Palindromic-sums.pl
131-Prime-cube-partnership.pl
138-Special-isosceles-triangles.pl
144-inner-reflections-in-ellipse.pl
145-reversible-digits.pl
148-Exploring-Pascals-triangle.pl
173-hollow-square-laminae.pl
174-counting-hollow-square-laminae.pl
179-Consecutive-positive-divisors.pl
187-semiprimes.pl
188-Tetration.pl
193-Squarefree-Numbers.pl
203-Squarefree-Binomial-Coefficients.pl
204-Generalized-Hamming-numbers.pl
205-Dice-game.pl
206-concealed-square.pl
211-Divisor-Square-Sum.pl
214-Totient-Chains.pl
226-A-scoop-of-blancmange.pl
283-ratio-between-triangle-area-and-perimeter.pl
297-Zeckendorf-representation.pl
301-Nim.pl
315-Digital-root-clocks.pl
323-Bitwise-OR.pl
345-Matrix-sum.pl
346-Strong-Repunits.pl
347-Largest-integer-divisible-by-2-primes.pl
349-Langtons-ant.pl
351-Hexagonal-orchards.pl
357-Prime-generating-integers.pl
381-prime-k-factorial.pl
387-Harshad-numbers.pl
407-Idempotents.pl
493-Under-the-Rainbow.pl
500-Problem-500.pl
504-Square-on-the-inside.pl
549-Divisibility-of-factorials.pl
577-Counting-hexagons.pl
587-Concave-triangle.pl
607-Marsh-crossing-1.pl
607-Marsh-crossing-2.pl
622-Riffle-Shuffles.pl
EulerHelper.pm
README.md
TODO.md

README.md

My Project Euler solutions

I reached 100 solved problems in Mar 2010, based on a blog post I made then.

I'm planning on cleaning up the solutions and uploading them to github going forward.

TODO

Separate entry.

Input data

Some problems load input data from files. These files are linked from the respective problem descriptions on Project Euler.

Perl modules

All solutions are coded in Perl 5. I've started to require 5.016 or newer in some files.

These modules are used:

  • EulerHelper, my own module with some helper functions
  • List::Util, this is a core module
  • Algorithm::Combinatorics
  • Date::Calc
  • Math::BigInt
  • Math::Prime::Util aka ntheory
  • Memoize