Solution to problem 12 in Julia

src/Julia/Problem012.jl

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+#=
+Created on 21 Jul 2021
+
+@author: David Doblas Jiménez
+@email: daviddoji@pm.me
+
+Solution for Problem 12 of Project Euler
+https://projecteuler.net/problem=12
+=#
+
+
+
+function Problem12()
+    #=
+     The sequence of triangle numbers is generated by adding the natural
+    numbers. So the 7th triangle number would be:
+    1 + 2 + 3 + 4 + 5 + 6 + 7 = 28.
+
+    The first ten terms would be:
+    1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
+
+    Let us list the factors of the first seven triangle numbers:
+
+     1: 1
+     3: 1,3
+     6: 1,2,3,6
+    10: 1,2,5,10
+    15: 1,3,5,15
+    21: 1,3,7,21
+    28: 1,2,4,7,14,28
+
+    We can see that 28 is the first triangle number to have over five divisors.
+
+    What is the value of the first triangle number to have over five hundred
+    divisors?
+    =#
+
+    function num_divisors(n)
+        res = floor(sqrt(n))
+        divs = []
+        for i in 1:res
+            if n%i == 0
+                append!(divs,i)
+            end
+        end
+        if res^2 == n
+            pop!(divs)
+        end
+        return 2*length(divs)
+    end
+
+    triangle = 0
+    for i in Iterators.countfrom(1)
+        triangle += i
+        if num_divisors(triangle) > 500
+            return string(triangle)
+        end
+    end
+end
+
+
+println("Time to evaluate Problem 12:")
+@time Problem12()
+println("")
+println("Result for Problem 12: ", Problem12())