Rebased projecteuler folder, now includes all contest programming stuff

projecteuler/026/main.py

@@ -0,0 +1,84 @@
+# Find the number d < 1000 for which 1 / d has the longest recurring cycle
+# in its decimal fraction part
+
+# It seems like the cycle is never longer than the longest of the cycle length of any of its prime divisors
+# So say we want to know the length for d and d = a * b, then the cycle for d has the same length as either the cycle for a or b, whichever is longer.
+
+# So it seems we then only have to check the primes, so first let's get a prime finder in here
+
+import numpy as np
+import math
+
+def maxIndex(ns):
+	result = 0
+	m = ns[0]
+
+	for i in range(len(ns)):
+		if ns[i] > m:
+			result = i
+			m = ns[i]
+
+	return result
+
+def getPrimes(n):
+	primes = [1 for p in range(n)]
+	primes[0] = 0
+	primes[1] = 0
+
+	x = 2
+	while x < np.sqrt(n):
+		if primes[x] == 1:
+
+			for i in range(x+x, n, x):
+				primes[i] = 0
+
+		x += 1
+
+	result = []
+	for i in range(n):
+		if primes[i]:
+			result.append(i)
+
+	return result
+
+# Now we need to find out the recurring cycle length for any number
+# As a benefit for only checking prime number, we know that the cycles will always immediately start after the .'s
+
+def cycleLength(n):
+	l = int(math.log10(n)) + 1
+	y = 1
+	power = pow(10,l)
+
+	result = 1
+	
+	while True:
+
+		x = (y * power) // n
+		rest = y * power - x * n
+
+		if rest == 0:
+			return 0
+		
+		elif rest == 1:
+			break
+		
+		else:
+			y = rest
+
+		result += 1
+
+	return result * l
+
+def main():
+	print("Hello, this is Patrick")
+
+	ps = getPrimes(1000)
+	cyclelengths = [cycleLength(p) for p in ps]
+	
+	for i in range(len(ps)):
+		print(f"{ps[i]} has length: {cyclelengths[i]}")
+
+	print(f"Biggest cycle is for {ps[maxIndex(cyclelengths)]} with length {max(cyclelengths)}")
+
+if __name__ == "__main__":
+	main()