Fib fast

Author: dwipam

practice/fib-_fast.py

@@ -0,0 +1,14 @@
+def fib(N):
+	if N == 0:
+	    return 0
+	if N == 1:
+	    return 1
+	prev_sum = 0
+	cur_sum = 1
+	total_sum = 1
+	for i in range(2,N+1):
+	    total_sum = cur_sum + prev_sum
+	    prev_sum = cur_sum
+	    cur_sum = total_sum
+	return total_sum
+print fib(5)