Solution to problem 42 in Julia

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David Doblas Jiménez 2021-09-12 16:33:54 +02:00
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src/Julia/Problem042.jl Normal file
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#=
Created on 12 Sep 2021
@author: David Doblas Jiménez
@email: daviddoji@pm.me
Solution for Problem 42 of Project Euler
https://projecteuler.net/problem=42
=#
using BenchmarkTools
using DelimitedFiles
function triangle_number(num)
return Int(0.5*num*(num+1))
end
function word_to_value(word)
return sum(Int(letter)-64 for letter in word)
end
function Problem42()
#=
The nth term of the sequence of triangle numbers is given by, tn = ½n(n+1);
so the first ten triangle numbers are:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
By converting each letter in a word to a number corresponding to its alphabetical
position and adding these values we form a word value. For example, the word value
for SKY is 19 + 11 + 25 = 55 = t10. If the word value is a triangle number then we
shall call the word a triangle word.
Using words.txt, a 16K text file containing nearly two-thousand common English words,
how many are triangle words?
=#
triangular_numbers = [triangle_number(n) for n in 1:26]
ans = 0
file = "/datos/Scripts/Gitea/Project_Euler/src/files/Problem42.txt"
words = sort(readdlm(file, ',', String)[:])
for word in words
if word_to_value(word) in triangular_numbers
ans += 1
end
end
return ans
end
println("Time to evaluate Problem 42:")
@btime Problem42()
println("")
println("Result for Problem 42: ", Problem42())