From 4033e9824d62a82cf7106442433d52dabc92b2ac Mon Sep 17 00:00:00 2001
From: riyalpatel <63769014+riyalpatel@users.noreply.github.com>
Date: Thu, 1 Oct 2020 11:26:25 +0530
Subject: [PATCH] Create 15.lattice_paths

---
 Python/15.lattice_paths | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 Python/15.lattice_paths

diff --git a/Python/15.lattice_paths b/Python/15.lattice_paths
new file mode 100644
index 0000000..674827d
--- /dev/null
+++ b/Python/15.lattice_paths
@@ -0,0 +1,25 @@
+#Import factorial from math module
+from math import factorial
+
+#import time from time to calculate exection time
+from time import time
+
+#time at the start of execution
+start = time()
+
+#binomial coefficient function
+#https://en.wikipedia.org/wiki/Binomial_coefficient
+def nck(n,k):
+	#function which will return the binomial coefficient
+	#of n,k
+	return factorial(n)/(factorial(k)*factorial(n-k))
+
+#Number of lattice paths from (0,0) to (a,b) is given by
+#binomial coefficient C(a+b,a)
+print 'Number of lattice paths is: '+str(nck(20+20,20))
+
+#time at the end of program execution
+end = time()
+
+#Printing the total time
+print end-start