Merge pull request #595 from lakshay-angrish/python-fast-fibonacci

Python fast fibonacci

Author: probot-auto-merge[bot]

Fibonacci Sequence/fast-fibonacci.py

@@ -0,0 +1,41 @@
+def fib(n): 
+    F = [[1, 1], 
+         [1, 0]] 
+    if (n == 0): 
+        return 0
+    power(F, n - 1) 
+      
+    return F[0][0] 
+  
+def multiply(F, M): 
+  
+    x = (F[0][0] * M[0][0] + 
+         F[0][1] * M[1][0]) 
+    y = (F[0][0] * M[0][1] +
+         F[0][1] * M[1][1]) 
+    z = (F[1][0] * M[0][0] + 
+         F[1][1] * M[1][0]) 
+    w = (F[1][0] * M[0][1] + 
+         F[1][1] * M[1][1]) 
+      
+    F[0][0] = x 
+    F[0][1] = y 
+    F[1][0] = z 
+    F[1][1] = w 
+  
+def power(F, n): 
+  
+    if( n == 0 or n == 1): 
+        return; 
+    M = [[1, 1], 
+         [1, 0]]; 
+          
+    power(F, n // 2) 
+    multiply(F, F) 
+          
+    if (n % 2 != 0): 
+        multiply(F, M) 
+
+
+n = 11
+print(fib(n))