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https://bitbucket.org/Mattrixwv/projecteulerlua.git
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82 lines
4.6 KiB
Lua
82 lines
4.6 KiB
Lua
--ProjectEuler/lua/Problem8.lua
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--Matthew Ellison
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-- Created: 02-06-19
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--Modified: 06-19-20
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--Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
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--[[
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73167176531330624919225119674426574742355349194934
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96983520312774506326239578318016984801869478851843
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85861560789112949495459501737958331952853208805511
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12540698747158523863050715693290963295227443043557
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66896648950445244523161731856403098711121722383113
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62229893423380308135336276614282806444486645238749
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30358907296290491560440772390713810515859307960866
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70172427121883998797908792274921901699720888093776
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65727333001053367881220235421809751254540594752243
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52584907711670556013604839586446706324415722155397
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53697817977846174064955149290862569321978468622482
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83972241375657056057490261407972968652414535100474
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82166370484403199890008895243450658541227588666881
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16427171479924442928230863465674813919123162824586
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17866458359124566529476545682848912883142607690042
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24219022671055626321111109370544217506941658960408
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07198403850962455444362981230987879927244284909188
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84580156166097919133875499200524063689912560717606
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05886116467109405077541002256983155200055935729725
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71636269561882670428252483600823257530420752963450
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]]
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--All of my requires, unless otherwise listed, can be found at https://bitbucket.org/Mattrixwv/luaClasses
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--[[
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Copyright (C) 2020 Matthew Ellison
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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]]
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require "Stopwatch"
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local timer = Stopwatch:create();
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timer:start();
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--Put the number into a variable. A string will do for now
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NUMBER = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
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local maxNum = ""; --Holds the largest number product we have found so far
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local maxProduct = 0; --Holds the product of what is currently stored in maxNum
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--Loop through all elements in the number string
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for location=13,string.len(NUMBER) do
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--Added 13 elements to it's own table
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local currentProduct = string.sub(NUMBER, location, location) * string.sub(NUMBER, location - 1, location - 1) * string.sub(NUMBER, location - 2, location - 2) * string.sub(NUMBER, location - 3, location - 3) * string.sub(NUMBER, location - 4, location - 4) * string.sub(NUMBER, location - 5, location - 5) * string.sub(NUMBER, location - 6, location - 6) * string.sub(NUMBER, location - 7, location - 7) * string.sub(NUMBER, location - 8, location - 8) * string.sub(NUMBER, location - 9, location - 9) * string.sub(NUMBER, location - 10, location - 10) * string.sub(NUMBER, location - 11, location - 11) * string.sub(NUMBER, location - 12, location - 12);
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--If the number is larger than the current max make it the max
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if(currentProduct > maxProduct) then
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maxProduct = currentProduct;
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maxNum = string.sub(NUMBER, location - 12, location);
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end
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end
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timer:stop();
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--Print the results
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print("The largest product of 13 adjacent digits in the number is " .. math.floor(maxProduct))
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print("The numbers are " .. maxNum);
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print("It took " .. timer:getMilliseconds() .. " milliseconds to run this algorithm");
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--[[Results:
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The largest product of 13 adjacent digits in the number is 23514624000
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The numbers are 5576689664895
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It took 2.662 milliseconds to run this algorithm
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]]
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