Solution to problem 58

src/Python/Problem058.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+"""
+Created on 10 Oct 2021
+
+@author: David Doblas Jiménez
+@email: daviddoji@pm.me
+
+Solution for problem 58 of Project Euler
+https://projecteuler.net/problem=58
+"""
+
+from utils import timeit, is_prime
+
+
+@timeit("Problem 58")
+def compute():
+    """
+    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 range(4):
+            num += side
+            corners.append(is_prime(num))
+        ratio = sum(corners) / len(corners)
+
+    return side + 1
+
+
+if __name__ == "__main__":
+
+    print(f"Result for Problem 58: {compute()}")