Solution to problem 17 in Julia

src/Julia/Problem017.jl

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+#=
+Created on 28 Jul 2021
+
+@author: David Doblas Jiménez
+@email: daviddoji@pm.me
+
+Solution for Problem 17 of Project Euler
+https://projecteuler.net/problem=17
+=#
+
+function num2letters(num)
+    nums = Dict(
+        0 => "", 1 => "one", 2 => "two", 3 => "three", 4 => "four", 5 => "five",
+        6 => "six", 7 => "seven", 8 => "eight", 9 => "nine", 10 => "ten",
+        11 => "eleven", 12 => "twelve", 13 => "thirteen", 14 => "fourteen",
+        15 => "fifteen", 16 => "sixteen", 17 => "seventeen", 18 => "eighteen",
+        19 => "nineteen", 20 => "twenty", 30 => "thirty", 40 => "forty",
+        50 => "fifty", 60 => "sixty", 70 => "seventy", 80 => "eighty",
+        90 => "ninety", 100 => "hundred", 1000 => "thousand"
+)
+
+    if num <= 20
+        return length(nums[num])
+    elseif num < 100
+        tens, units = divrem(num, 10)
+        return length(nums[tens * 10]) + num2letters(units)
+    elseif num < 1000
+        hundreds, rest = divrem(num, 100)
+        if rest != 0
+            return num2letters(hundreds) + length(nums[100]) + length("and") + num2letters(rest)
+        else
+            return num2letters(hundreds) + length(nums[100])
+        end
+    else
+        thousands, rest = divrem(num, 1000)
+        return num2letters(thousands) + length(nums[1000])
+    end
+end
+
+function Problem17()
+    #=
+    If the numbers 1 to 5 are written out in words: one, two, three, four,
+    five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.
+
+    If all the numbers from 1 to 1000 (one thousand) inclusive were written
+    out in words, how many letters would be used?
+
+    NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and
+    forty-two) contains 23 letters and 115 (one hundred and fifteen) contains
+    20 letters. The use of "and" when writing out numbers is in compliance
+    with British usage.
+    =#
+    n = 1000
+    letters = 0
+    for num in 1:n
+        letters += num2letters(num)
+    end
+    return letters
+end
+
+
+println("Time to evaluate Problem 17:")
+@time Problem17()
+println("")
+println("Result for Problem 17: ", Problem17())