Solution to problem 58 in julia

src/Julia/Problem058.jl

@@ -0,0 +1,58 @@
+#=
+Created on 11 Oct 2021
+
+@author: David Doblas Jiménez
+@email: daviddoji@pm.me
+
+Solution for Problem 58 of Project Euler
+https://projecteuler.net/problem=58
+=#
+
+using BenchmarkTools
+using Primes
+
+function Problem58()
+    #=
+    Starting with 1 and spiralling anticlockwise in the following way,
+    a square spiral with side length 7 is formed.
+
+        37 36 35 34 33 32 31
+        38 17 16 15 14 13 30
+        39 18  5  4  3 12 29
+        40 19  6  1  2 11 28
+        41 20  7  8  9 10 27
+        42 21 22 23 24 25 26
+        43 44 45 46 47 48 49
+
+    It is interesting to note that the odd squares lie along the bottom right
+    diagonal, but what is more interesting is that 8 out of the 13 numbers
+    lying along both diagonals are prime; that is, a ratio of 8/13 ≈ 62%.
+
+    If one complete new layer is wrapped around the spiral above, a square
+    spiral with side length 9 will be formed. If this process is continued,
+    what is the side length of the square spiral for which the ratio of primes
+    along both diagonals first falls below 10%?
+    =#
+
+    ratio = 1
+    corners = []
+    side = 0
+    num = 1
+
+    while ratio > 0.1
+        side += 2
+        for _ in 1:4
+            num += side
+            push!(corners, isprime(num))
+        end
+        ratio = sum(corners) / length(corners)
+    end
+
+    return side + 1
+end
+
+
+println("Time to evaluate Problem 58:")
+@btime Problem58()
+println("")
+println("Result for Problem 58: ", Problem58())