Solution to problem 25

src/Python/Problem025.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+"""
+Created on 11 Sep 2019
+
+@author: David Doblas Jiménez
+@email: daviddoji@pm.me
+
+Solution for problem 25 of Project Euler
+https://projecteuler.net/problem=25
+"""
+
+from utils import timeit
+
+
+@timeit("Problem 25")
+def compute():
+    """
+    The Fibonacci sequence is defined by the recurrence relation:
+
+        Fn = Fn−1 + Fn−2, where F1 = 1 and F2 = 1.
+
+    Hence the first 12 terms will be:
+
+        F1 = 1
+        F2 = 1
+        F3 = 2
+        F4 = 3
+        F5 = 5
+        F6 = 8
+        F7 = 13
+        F8 = 21
+        F9 = 34
+        F10 = 55
+        F11 = 89
+        F12 = 144
+
+    The 12th term, F12, is the first term to contain three digits.
+
+    What is the index of the first term in the Fibonacci sequence to
+    contain 1000 digits?
+    """
+    a, b = 1, 1
+    index = 2
+
+    while len(str(b)) < 1000:
+        a, b = b, b+a
+        index += 1
+
+    return index
+
+
+if __name__ == "__main__":
+
+    print(f"Result for Problem 25: {compute()}")