hacktoberfest-projecteuler

This repo contains solutions for projecteuler problems. Specially created for newcomers to contribute as part of Hacktoberfest Challenge.

Kind request to everyone that before sending any pull request test your solutions on projecteuler.net.

List of Problems

Problem #1 Multiples of 3 and 5 || solutions
Problem #2 Even Fibonacci numbers || solutions
Problem #3 Largest prime factor || solutions
Problem #4 Largest palindrome product || solutions
Problem #5 Smallest multiple || solutions
Problem #6 Sum square difference || solutions
Problem #7 10001st prime || solutions
Problem #8 Largest product in a series || solutions
Problem #9 Special Pythagorean triplet || solutions
Problem #10 Summation of primes || solutions
Problem #11 Largest product in a grid || solutions
Problem #12 Highly divisible triangular number || solutions
Problem #13 Large sum || solutions
Problem #14 Longest Collatz sequence || solutions
Problem #15 Lattice paths || solutions
Problem #16 Power digit sum || solutions
Problem #17 Number letter counts || solutions
Problem #18 Maximum path sum I || solutions
Problem #19 Counting Sundays || solutions
Problem #20 Factorial digit sum || solutions
Problem #21 Amicable numbers || solutions
Problem #22 Names scores || solutions
Problem #23 Non-abundant sums || solutions
Problem #24 Lexicographic permutations || solutions
Problem #25 1000-digit Fibonacci number || solutions
Problem #26 Reciprocal cycles || solutions
Problem #27 Quadratic primes || solutions
Problem #28 Number spiral diagonals || solutions
Problem #29 Distinct powers || solutions
Problem #30 Digit fifth powers || solutions
Problem #31 Coin sums || solutions
Problem #32 Pandigital products || solutions
Problem #33 Digit cancelling fractions || solutions
Problem #34 Digit factorials || solutions
Problem #35 Circular primes || solutions
Problem #36 Double-base palindromes || solutions
Problem #37 Truncatable primes || solutions
Problem #38 Pandigital multiples || solutions
Problem #39 Integer right triangles || solutions
Problem #40 Champernowne's constant || solutions
Problem #41 Pandigital prime || solutions
Problem #42 Coded triangle numbers || solutions
Problem #43 Sub-string divisibility || solutions
Problem #44 Pentagon numbers || solutions
Problem #45 Triangular, pentagonal, and hexagonal || solutions
Problem #46 Goldbach's other conjecture || solutions
Problem #47 Distinct primes factors || solutions
Problem #48 Self powers || solutions
Problem #49 Prime permutations || solutions
Problem #50 Consecutive prime sum || solutions
Problem #51 Prime digit replacements || solutions
Problem #52 Permuted multiples || solutions
Problem #53 Combinatoric selections || solutions
Problem #54 Poker hands || solutions
Problem #55 Lychrel numbers || solutions
Problem #56 Powerful digit sum || solutions
Problem #57 Square root convergents || solutions
Problem #58 Spiral primes || solutions
Problem #59 XOR decryption || solutions
Problem #60 Prime pair sets || solutions
Problem #61 Cyclical figurate numbers || solutions
Problem #62 Cubic permutations || solutions
Problem #63 Powerful digit counts || solutions
Problem #64 Odd period square roots || solutions
Problem #65 Convergents of e || solutions
Problem #66 Diophantine equation || solutions
Problem #67 Maximum path sum II || solutions
Problem #68 Magic 5-gon ring || solutions
Problem #69 Totient maximum || solutions
Problem #70 Totient permutation || solutions
Problem #71 Ordered fractions || solutions
Problem #72 Counting fractions || solutions
Problem #73 Counting fractions in a range || solutions
Problem #74 Digit factorial chains || solutions
Problem #75 Singular integer right triangles || solutions
Problem #76 Counting summations || solutions
Problem #77 Prime summations || solutions
Problem #78 Coin partitions || solutions
Problem #79 Passcode derivation || solutions
Problem #80 Square root digital expansion || solutions
Problem #81 Path sum: two ways || solutions
Problem #82 Path sum: three ways || solutions
Problem #83 Path sum: four ways || solutions
Problem #84 Monopoly odds || solutions
Problem #85 Counting rectangles || solutions
Problem #86 Cuboid route || solutions
Problem #87 Prime power triples || solutions
Problem #88 Product-sum numbers || solutions
Problem #89 Roman numerals || solutions
Problem #90 Cube digit pairs || solutions
Problem #91 Right triangles with integer coordinates || solutions
Problem #92 Square digit chains || solutions
Problem #93 Arithmetic expressions || solutions
Problem #94 Almost equilateral triangles || solutions
Problem #95 Amicable chains || solutions
Problem #96 Su Doku || solutions
Problem #97 Large non-Mersenne prime || solutions
Problem #98 Anagramic squares || solutions
Problem #99 Largest exponential || solutions
Problem #100 Arranged probability || solutions
Problem #101 Optimum polynomial || solutions
Problem #102 Triangle containment || solutions
Problem #103 Special subset sums: optimum || solutions
Problem #104 Pandigital Fibonacci ends || solutions
Problem #105 Special subset sums: testing || solutions
Problem #106 Special subset sums: meta-testing || solutions
Problem #107 Minimal network || solutions
Problem #108 Diophantine reciprocals I || solutions
Problem #109 Darts || solutions
Problem #110 Diophantine reciprocals II || solutions
Problem #111 Primes with runs || solutions
Problem #112 Bouncy numbers || solutions
Problem #113 Non-bouncy numbers || solutions
Problem #114 Counting block combinations I || solutions
Problem #115 Counting block combinations II || solutions
Problem #116 Red, green or blue tiles || solutions
Problem #117 Red, green, and blue tiles || solutions
Problem #118 Pandigital prime sets || solutions
Problem #119 Digit power sum || solutions
Problem #120 Square remainders || solutions
Problem #121 Disc game prize fund || solutions
Problem #122 Efficient exponentiation || solutions
Problem #123 Prime square remainders || solutions
Problem #124 Ordered radicals || solutions
Problem #125 Palindromic sums || solutions
Problem #126 Cuboid layers || solutions
Problem #127 abc-hits || solutions
Problem #128 Hexagonal tile differences || solutions
Problem #129 Repunit divisibility || solutions
Problem #130 Composites with prime repunit property || solutions
Problem #131 Prime cube partnership || solutions
Problem #132 Large repunit factors || solutions
Problem #133 Repunit nonfactors || solutions
Problem #134 Prime pair connection || solutions
Problem #135 Same differences || solutions
Problem #136 Singleton difference || solutions
Problem #137 Fibonacci golden nuggets || solutions
Problem #138 Special isosceles triangles || solutions
Problem #139 Pythagorean tiles || solutions
Problem #140 Modified Fibonacci golden nuggets || solutions
Problem #141 Investigating progressive numbers, n, which are also square || solutions
Problem #142 Perfect Square Collection || solutions
Problem #143 Investigating the Torricelli point of a triangle || solutions
Problem #144 Investigating multiple reflections of a laser beam || solutions
Problem #145 How many reversible numbers are there below one-billion? || solutions
Problem #146 Investigating a Prime Pattern || solutions
Problem #147 Rectangles in cross-hatched grids || solutions
Problem #148 Exploring Pascal's triangle || solutions
Problem #149 Searching for a maximum-sum subsequence || solutions
Problem #150 Searching a triangular array for a sub-triangle having minimum-sum || solutions
Problem #151 Paper sheets of standard sizes: an expected-value problem || solutions
Problem #152 Writing 1/2 as a sum of inverse squares || solutions
Problem #153 Investigating Gaussian Integers || solutions
Problem #154 Exploring Pascal's pyramid || solutions
Problem #155 Counting Capacitor Circuits || solutions
Problem #156 Counting Digits || solutions
Problem #157 Solving the diophantine equation 1/a+1/b= p/10n || solutions
Problem #158 Exploring strings for which only one character comes lexicographically after its neighbour to the left || solutions
Problem #159 Digital root sums of factorisations || solutions
Problem #160 Factorial trailing digits || solutions
Problem #161 Triominoes || solutions
Problem #162 Hexadecimal numbers || solutions
Problem #163 Cross-hatched triangles || solutions
Problem #164 Numbers for which no three consecutive digits have a sum greater than a given value || solutions
Problem #165 Intersections || solutions
Problem #166 Criss Cross || solutions
Problem #167 Investigating Ulam sequences || solutions
Problem #168 Number Rotations || solutions
Problem #169 Exploring the number of different ways a number can be expressed as a sum of powers of 2 || solutions
Problem #170 Find the largest 0 to 9 pandigital that can be formed by concatenating products || solutions
Problem #171 Finding numbers for which the sum of the squares of the digits is a square || solutions
Problem #172 Investigating numbers with few repeated digits || solutions
Problem #173 Using up to one million tiles how many different "hollow" square laminae can be formed? || solutions
Problem #174 Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements || solutions
Problem #175 Fractions involving the number of different ways a number can be expressed as a sum of powers of 2 || solutions
Problem #176 Right-angled triangles that share a cathetus || solutions
Problem #177 Integer angled Quadrilaterals || solutions
Problem #178 Step Numbers || solutions
Problem #179 Consecutive positive divisors || solutions
Problem #180 Rational zeros of a function of three variables || solutions
Problem #181 Investigating in how many ways objects of two different colours can be grouped || solutions
Problem #182 RSA encryption || solutions
Problem #183 Maximum product of parts || solutions
Problem #184 Triangles containing the origin || solutions
Problem #185 Number Mind || solutions
Problem #186 Connectedness of a network || solutions
Problem #187 Semiprimes || solutions
Problem #188 The hyperexponentiation of a number || solutions
Problem #189 Tri-colouring a triangular grid || solutions
Problem #190 Maximising a weighted product || solutions
Problem #191 Prize Strings || solutions
Problem #192 Best Approximations || solutions
Problem #193 Squarefree Numbers || solutions
Problem #194 Coloured Configurations || solutions
Problem #195 Inscribed circles of triangles with one angle of 60 degrees || solutions
Problem #196 Prime triplets || solutions
Problem #197 Investigating the behaviour of a recursively defined sequence || solutions
Problem #198 Ambiguous Numbers || solutions
Problem #199 Iterative Circle Packing || solutions
Problem #200 Find the 200th prime-proof sqube containing the contiguous sub-string "200" || solutions
Problem #201 Subsets with a unique sum || solutions
Problem #202 Laserbeam || solutions
Problem #203 Squarefree Binomial Coefficients || solutions
Problem #204 Generalised Hamming Numbers || solutions
Problem #205 Dice Game || solutions
Problem #206 Concealed Square || solutions
Problem #207 Integer partition equations || solutions
Problem #208 Robot Walks || solutions
Problem #209 Circular Logic || solutions
Problem #210 Obtuse Angled Triangles || solutions
Problem #211 Divisor Square Sum || solutions
Problem #212 Combined Volume of Cuboids || solutions
Problem #213 Flea Circus || solutions
Problem #214 Totient Chains || solutions
Problem #215 Crack-free Walls || solutions
Problem #216 Investigating the primality of numbers of the form 2n2-1 || solutions
Problem #217 Balanced Numbers || solutions
Problem #218 Perfect right-angled triangles || solutions
Problem #219 Skew-cost coding || solutions
Problem #220 Heighway Dragon || solutions
Problem #221 Alexandrian Integers || solutions
Problem #222 Sphere Packing || solutions
Problem #223 Almost right-angled triangles I || solutions
Problem #224 Almost right-angled triangles II || solutions
Problem #225 Tribonacci non-divisors || solutions
Problem #226 A Scoop of Blancmange || solutions
Problem #227 The Chase || solutions
Problem #228 Minkowski Sums || solutions
Problem #229 Four Representations using Squares || solutions
Problem #230 Fibonacci Words || solutions
Problem #231 The prime factorisation of binomial coefficients || solutions
Problem #232 The Race || solutions
Problem #233 Lattice points on a circle || solutions
Problem #234 Semidivisible numbers || solutions
Problem #235 An Arithmetic Geometric sequence || solutions
Problem #236 Luxury Hampers || solutions
Problem #237 Tours on a 4 x n playing board || solutions
Problem #238 Infinite string tour || solutions
Problem #239 Twenty-two Foolish Primes || solutions
Problem #240 Top Dice || solutions
Problem #241 Perfection Quotients || solutions
Problem #242 Odd Triplets || solutions
Problem #243 Resilience || solutions
Problem #244 Sliders || solutions
Problem #245 Coresilience || solutions
Problem #246 Tangents to an ellipse || solutions
Problem #247 Squares under a hyperbola || solutions
Problem #248 Numbers for which Euler’s totient function equals 13! || solutions
Problem #249 Prime Subset Sums || solutions
Problem #250 250250 || solutions
Problem #251 Cardano Triplets || solutions
Problem #252 Convex Holes || solutions
Problem #253 Tidying up || solutions
Problem #254 Sums of Digit Factorials || solutions
Problem #255 Rounded Square Roots || solutions
Problem #256 Tatami-Free Rooms || solutions
Problem #257 Angular Bisectors || solutions
Problem #258 A lagged Fibonacci sequence || solutions
Problem #259 Reachable Numbers || solutions
Problem #260 Stone Game || solutions
Problem #261 Pivotal Square Sums || solutions
Problem #262 Mountain Range || solutions
Problem #263 An engineers' dream come true || solutions
Problem #264 Triangle Centres || solutions
Problem #265 Binary Circles || solutions
Problem #266 Pseudo Square Root || solutions
Problem #267 Billionaire || solutions
Problem #268 Counting numbers with at least four distinct prime factors less than 100 || solutions
Problem #269 Polynomials with at least one integer root || solutions
Problem #270 Cutting Squares || solutions
Problem #271 Modular Cubes, part 1 || solutions
Problem #272 Modular Cubes, part 2 || solutions
Problem #273 Sum of Squares || solutions
Problem #274 Divisibility Multipliers || solutions
Problem #275 Balanced Sculptures || solutions
Problem #276 Primitive Triangles || solutions
Problem #277 A Modified Collatz sequence || solutions
Problem #278 Linear Combinations of Semiprimes || solutions
Problem #279 Triangles with integral sides and an integral angle || solutions
Problem #280 Ant and seeds || solutions
Problem #281 Pizza Toppings || solutions
Problem #282 The Ackermann function || solutions
Problem #283 Integer sided triangles for which the area/perimeter ratio is integral || solutions
Problem #284 Steady Squares || solutions
Problem #285 Pythagorean odds || solutions
Problem #286 Scoring probabilities || solutions
Problem #287 Quadtree encoding (a simple compression algorithm) || solutions
Problem #288 An enormous factorial || solutions
Problem #289 Eulerian Cycles || solutions
Problem #290 Digital Signature || solutions
Problem #291 Panaitopol Primes || solutions
Problem #292 Pythagorean Polygons || solutions
Problem #293 Pseudo-Fortunate Numbers || solutions
Problem #294 Sum of digits - experience #23 || solutions
Problem #295 Lenticular holes || solutions
Problem #296 Angular Bisector and Tangent || solutions
Problem #297 Zeckendorf Representation || solutions
Problem #298 Selective Amnesia || solutions
Problem #299 Three similar triangles || solutions
Problem #300 Protein folding || solutions
Problem #301 Nim || solutions
Problem #302 Strong Achilles Numbers || solutions
Problem #303 Multiples with small digits || solutions
Problem #304 Primonacci || solutions
Problem #305 Reflexive Position || solutions
Problem #306 Paper-strip Game || solutions
Problem #307 Chip Defects || solutions
Problem #308 An amazing Prime-generating Automaton || solutions
Problem #309 Integer Ladders || solutions
Problem #310 Nim Square || solutions
Problem #311 Biclinic Integral Quadrilaterals || solutions
Problem #312 Cyclic paths on Sierpiński graphs || solutions
Problem #313 Sliding game || solutions
Problem #314 The Mouse on the Moon || solutions
Problem #315 Digital root clocks || solutions
Problem #316 Numbers in decimal expansions || solutions
Problem #317 Firecracker || solutions
Problem #318 2011 nines || solutions
Problem #319 Bounded Sequences || solutions
Problem #320 Factorials divisible by a huge integer || solutions
Problem #321 Swapping Counters || solutions
Problem #322 Binomial coefficients divisible by 10 || solutions
Problem #323 Bitwise-OR operations on random integers || solutions
Problem #324 Building a tower || solutions
Problem #325 Stone Game II || solutions
Problem #326 Modulo Summations || solutions
Problem #327 Rooms of Doom || solutions
Problem #328 Lowest-cost Search || solutions
Problem #329 Prime Frog || solutions
Problem #330 Euler's Number || solutions
Problem #331 Cross flips || solutions
Problem #332 Spherical triangles || solutions
Problem #333 Special partitions || solutions
Problem #334 Spilling the beans || solutions
Problem #335 Gathering the beans || solutions
Problem #336 Maximix Arrangements || solutions
Problem #337 Totient Stairstep Sequences || solutions
Problem #338 Cutting Rectangular Grid Paper || solutions
Problem #339 Peredur fab Efrawg || solutions
Problem #340 Crazy Function || solutions
Problem #341 Golomb's self-describing sequence || solutions
Problem #342 The totient of a square is a cube || solutions
Problem #343 Fractional Sequences || solutions
Problem #344 Silver dollar game || solutions
Problem #345 Matrix Sum || solutions
Problem #346 Strong Repunits || solutions
Problem #347 Largest integer divisible by two primes || solutions
Problem #348 Sum of a square and a cube || solutions
Problem #349 Langton's ant || solutions
Problem #350 Constraining the least greatest and the greatest least || solutions
Problem #351 Hexagonal orchards || solutions
Problem #352 Blood tests || solutions
Problem #353 Risky moon || solutions
Problem #354 Distances in a bee's honeycomb || solutions
Problem #355 Maximal coprime subset || solutions
Problem #356 Largest roots of cubic polynomials || solutions
Problem #357 Prime generating integers || solutions
Problem #358 Cyclic numbers || solutions
Problem #359 Hilbert's New Hotel || solutions
Problem #360 Scary Sphere || solutions
Problem #361 Subsequence of Thue-Morse sequence || solutions
Problem #362 Squarefree factors || solutions
Problem #363 Bézier Curves || solutions
Problem #364 Comfortable distance || solutions
Problem #365 A huge binomial coefficient || solutions
Problem #366 Stone Game III || solutions
Problem #367 Bozo sort || solutions
Problem #368 A Kempner-like series || solutions
Problem #369 Badugi || solutions
Problem #370 Geometric triangles || solutions
Problem #371 Licence plates || solutions
Problem #372 Pencils of rays || solutions
Problem #373 Circumscribed Circles || solutions
Problem #374 Maximum Integer Partition Product || solutions
Problem #375 Minimum of subsequences || solutions
Problem #376 Nontransitive sets of dice || solutions
Problem #377 Sum of digits, experience 13 || solutions
Problem #378 Triangle Triples || solutions
Problem #379 Least common multiple count || solutions
Problem #380 Amazing Mazes! || solutions
Problem #381 (prime-k) factorial || solutions
Problem #382 Generating polygons || solutions
Problem #383 Divisibility comparison between factorials || solutions
Problem #384 Rudin-Shapiro sequence || solutions
Problem #385 Ellipses inside triangles || solutions
Problem #386 Maximum length of an antichain || solutions
Problem #387 Harshad Numbers || solutions
Problem #388 Distinct Lines || solutions
Problem #389 Platonic Dice || solutions
Problem #390 Triangles with non rational sides and integral area || solutions
Problem #391 Hopping Game || solutions
Problem #392 Enmeshed unit circle || solutions
Problem #393 Migrating ants || solutions
Problem #394 Eating pie || solutions
Problem #395 Pythagorean tree || solutions
Problem #396 Weak Goodstein sequence || solutions
Problem #397 Triangle on parabola || solutions
Problem #398 Cutting rope || solutions
Problem #399 Squarefree Fibonacci Numbers || solutions
Problem #400 Fibonacci tree game || solutions
Problem #401 Sum of squares of divisors || solutions
Problem #402 Integer-valued polynomials || solutions
Problem #403 Lattice points enclosed by parabola and line || solutions
Problem #404 Crisscross Ellipses || solutions
Problem #405 A rectangular tiling || solutions
Problem #406 Guessing Game || solutions
Problem #407 Idempotents || solutions
Problem #408 Admissible paths through a grid || solutions
Problem #409 Nim Extreme || solutions
Problem #410 Circle and tangent line || solutions
Problem #411 Uphill paths || solutions
Problem #412 Gnomon numbering || solutions
Problem #413 One-child Numbers || solutions
Problem #414 Kaprekar constant || solutions
Problem #415 Titanic sets || solutions
Problem #416 A frog's trip || solutions
Problem #417 Reciprocal cycles II || solutions
Problem #418 Factorisation triples || solutions
Problem #419 Look and say sequence || solutions
Problem #420 2x2 positive integer matrix || solutions
Problem #421 Prime factors of n15+1 || solutions
Problem #422 Sequence of points on a hyperbola || solutions
Problem #423 Consecutive die throws || solutions
Problem #424 Kakuro || solutions
Problem #425 Prime connection || solutions
Problem #426 Box-ball system || solutions
Problem #427 n-sequences || solutions
Problem #428 Necklace of circles || solutions
Problem #429 Sum of squares of unitary divisors || solutions
Problem #430 Range flips || solutions
Problem #431 Square Space Silo || solutions
Problem #432 Totient sum || solutions
Problem #433 Steps in Euclid's algorithm || solutions
Problem #434 Rigid graphs || solutions
Problem #435 Polynomials of Fibonacci numbers || solutions
Problem #436 Unfair wager || solutions
Problem #437 Fibonacci primitive roots || solutions
Problem #438 Integer part of polynomial equation's solutions || solutions
Problem #439 Sum of sum of divisors || solutions
Problem #440 GCD and Tiling || solutions
Problem #441 The inverse summation of coprime couples || solutions
Problem #442 Eleven-free integers || solutions
Problem #443 GCD sequence || solutions
Problem #444 The Roundtable Lottery || solutions
Problem #445 Retractions A || solutions
Problem #446 Retractions B || solutions
Problem #447 Retractions C || solutions
Problem #448 Average least common multiple || solutions
Problem #449 Chocolate covered candy || solutions
Problem #450 Hypocycloid and Lattice points || solutions
Problem #451 Modular inverses || solutions
Problem #452 Long Products || solutions
Problem #453 Lattice Quadrilaterals || solutions
Problem #454 Diophantine reciprocals III || solutions
Problem #455 Powers With Trailing Digits || solutions
Problem #456 Triangles containing the origin II || solutions
Problem #457 A polynomial modulo the square of a prime || solutions
Problem #458 Permutations of Project || solutions
Problem #459 Flipping game || solutions
Problem #460 An ant on the move || solutions
Problem #461 Almost Pi || solutions
Problem #462 Permutation of 3-smooth numbers || solutions
Problem #463 A weird recurrence relation || solutions
Problem #464 Möbius function and intervals || solutions
Problem #465 Polar polygons || solutions
Problem #466 Distinct terms in a multiplication table || solutions
Problem #467 Superinteger || solutions
Problem #468 Smooth divisors of binomial coefficients || solutions
Problem #469 Empty chairs || solutions
Problem #470 Super Ramvok || solutions
Problem #471 Triangle inscribed in ellipse || solutions
Problem #472 Comfortable Distance II || solutions
Problem #473 Phigital number base || solutions
Problem #474 Last digits of divisors || solutions
Problem #475 Music festival || solutions
Problem #476 Circle Packing II || solutions
Problem #477 Number Sequence Game || solutions
Problem #478 Mixtures || solutions
Problem #479 Roots on the Rise || solutions
Problem #480 The Last Question || solutions
Problem #481 Chef Showdown || solutions
Problem #482 The incenter of a triangle || solutions
Problem #483 Repeated permutation || solutions
Problem #484 Arithmetic Derivative || solutions
Problem #485 Maximum number of divisors || solutions
Problem #486 Palindrome-containing strings || solutions
Problem #487 Sums of power sums || solutions
Problem #488 Unbalanced Nim || solutions
Problem #489 Common factors between two sequences || solutions
Problem #490 Jumping frog || solutions
Problem #491 Double pandigital number divisible by 11 || solutions
Problem #492 Exploding sequence || solutions
Problem #493 Under The Rainbow || solutions
Problem #494 Collatz prefix families || solutions
Problem #495 Writing n as the product of k distinct positive integers || solutions
Problem #496 Incenter and circumcenter of triangle || solutions
Problem #497 Drunken Tower of Hanoi || solutions
Problem #498 Remainder of polynomial division || solutions
Problem #499 St. Petersburg Lottery || solutions
Problem #500 Problem 500!!! || solutions
Problem #501 Eight Divisors || solutions
Problem #502 Counting Castles || solutions
Problem #503 Compromise or persist || solutions
Problem #504 Square on the Inside || solutions
Problem #505 Bidirectional Recurrence || solutions
Problem #506 Clock sequence || solutions
Problem #507 Shortest Lattice Vector || solutions
Problem #508 Integers in base i-1 || solutions
Problem #509 Divisor Nim || solutions
Problem #510 Tangent Circles || solutions
Problem #511 Sequences with nice divisibility properties || solutions
Problem #512 Sums of totients of powers || solutions
Problem #513 Integral median || solutions
Problem #514 Geoboard Shapes || solutions
Problem #515 Dissonant Numbers || solutions
Problem #516 5-smooth totients || solutions
Problem #517 A real recursion || solutions
Problem #518 Prime triples and geometric sequences || solutions
Problem #519 Tricolored Coin Fountains || solutions
Problem #520 Simbers || solutions
Problem #521 Smallest prime factor || solutions
Problem #522 Hilbert's Blackout || solutions
Problem #523 First Sort I || solutions
Problem #524 First Sort II || solutions
Problem #525 Rolling Ellipse || solutions
Problem #526 Largest prime factors of consecutive numbers || solutions
Problem #527 Randomized Binary Search || solutions
Problem #528 Constrained Sums || solutions
Problem #529 10-substrings || solutions
Problem #530 GCD of Divisors || solutions
Problem #531 Chinese leftovers || solutions
Problem #532 Nanobots on Geodesics || solutions
Problem #533 Minimum values of the Carmichael function || solutions
Problem #534 Weak Queens || solutions
Problem #535 Fractal Sequence || solutions
Problem #536 Modulo power identity || solutions
Problem #537 Counting tuples || solutions
Problem #538 Maximum quadrilaterals || solutions
Problem #539 Odd elimination || solutions
Problem #540 Counting primitive Pythagorean triples || solutions
Problem #541 Divisibility of Harmonic Number Denominators || solutions
Problem #542 Geometric Progression with Maximum Sum || solutions
Problem #543 Prime-Sum Numbers || solutions
Problem #544 Chromatic Conundrum || solutions
Problem #545 Faulhaber's Formulas || solutions
Problem #546 The Floor's Revenge || solutions
Problem #547 Distance of random points within hollow square laminae || solutions
Problem #548 Gozinta Chains || solutions
Problem #549 Divisibility of factorials || solutions
Problem #550 Divisor game || solutions
Problem #551 Sum of digits sequence || solutions
Problem #552 Chinese leftovers II || solutions
Problem #553 Power sets of power sets || solutions
Problem #554 Centaurs on a chess board || solutions
Problem #555 McCarthy 91 function || solutions
Problem #556 Squarefree Gaussian Integers || solutions
Problem #557 Cutting triangles || solutions
Problem #558 Irrational base || solutions
Problem #559 Permuted Matrices || solutions
Problem #560 Coprime Nim || solutions
Problem #561 Divisor Pairs || solutions
Problem #562 Maximal perimeter || solutions
Problem #563 Robot Welders || solutions
Problem #564 Maximal polygons || solutions
Problem #565 Divisibility of sum of divisors || solutions
Problem #566 Cake Icing Puzzle || solutions
Problem #567 Reciprocal games I || solutions
Problem #568 Reciprocal games II || solutions
Problem #569 Prime Mountain Range || solutions
Problem #570 Snowflakes || solutions
Problem #571 Super Pandigital Numbers || solutions
Problem #572 Idempotent matrices || solutions
Problem #573 Unfair race || solutions
Problem #574 Verifying Primes || solutions
Problem #575 Wandering Robots || solutions
Problem #576 Irrational jumps || solutions
Problem #577 Counting hexagons || solutions
Problem #578 Integers with decreasing prime powers || solutions
Problem #579 Lattice points in lattice cubes || solutions
Problem #580 Squarefree Hilbert numbers || solutions
Problem #581 47-smooth triangular numbers || solutions
Problem #582 Nearly isosceles 120 degree triangles || solutions
Problem #583 Heron Envelopes || solutions
Problem #584 Birthday Problem Revisited || solutions
Problem #585 Nested square roots || solutions
Problem #586 Binary Quadratic Form || solutions
Problem #587 Concave triangle || solutions
Problem #588 Quintinomial coefficients || solutions
Problem #589 Poohsticks Marathon || solutions
Problem #590 Sets with a given Least Common Multiple || solutions
Problem #591 Best Approximations by Quadratic Integers || solutions
Problem #592 Factorial trailing digits 2 || solutions
Problem #593 Fleeting Medians || solutions
Problem #594 Rhombus Tilings || solutions
Problem #595 Incremental Random Sort || solutions
Problem #596 Number of lattice points in a hyperball || solutions
Problem #597 Torpids || solutions
Problem #598 Split Divisibilities || solutions
Problem #599 Distinct Colourings of a Rubik's Cube || solutions
Problem #600 Integer sided equiangular hexagons || solutions
Problem #601 Divisibility streaks || solutions
Problem #602 Product of Head Counts || solutions

savyad/hacktoberfest-projecteuler

hacktoberfest-projecteuler

List of Problems