Solution to problem 28 in Julia

src/Julia/Problem028.jl

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+#=
+Created on 23 Aug 2021
+
+@author: David Doblas Jiménez
+@email: daviddoji@pm.me
+
+Solution for Problem 28 of Project Euler
+https://projecteuler.net/problem=28
+=#
+
+using BenchmarkTools
+
+function Problem28()
+    #=
+    Starting with the number 1 and moving to the right in a clockwise
+    direction a 5 by 5 spiral is formed as follows:
+
+                                21 22 23 24 25
+                                20  7  8  9 10
+                                19  6  1  2 11
+                                18  5  4  3 12
+                                17 16 15 14 13
+
+    It can be verified that the sum of the numbers on the diagonals is 101.
+
+    What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral
+    formed in the same way?
+    =#
+    size = 1001  # Must be odd
+    ans = 1   # Special case for size 1
+    step = 0
+    i, cur = 1, 1
+    while step < size-1
+        step = i * 2
+        for j in 1:4
+            cur += step
+            ans += cur
+        end
+        i += 1
+    end
+
+    return ans
+end
+
+
+println("Time to evaluate Problem 28:")
+@btime Problem28()
+println("")
+println("Result for Problem 28: ", Problem28())