Project Euler problem 15

project_euler/p015_LatticePath.py

@@ -1,26 +1,19 @@
-/* Check cf5-opt.vim defs.
-VIM: let g:lcppflags="-std=c++11 -O2 -pthread"
-VIM: let g:wcppflags="/O2 /EHsc /DWIN32"
-*/
-#include <iostream>
+#Lattice paths
+#Problem 15
+#
+#Starting in the top left corner of a 2x2 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.
+#__   _    _       
+#  |   |_   |   |   |_    |__ 
+#  |     |  |_  |__   |_     |
+#
+#How many such routes are there through a 20x20 grid?
+#
+#Solution:
 
-/*
-Lattice paths
-Problem 15
-
-Starting in the top left corner of a 2x2 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.
-__   _    _       
-  |   |_   |   |   |_    |__ 
-  |     |  |_  |__   |_     |
-
-How many such routes are there through a 20x20 grid?
-
-Solution:
-*/
-
-int main ( void )
-{
-
-	return 0;
-}
+a = 1
+b = 1
+for i in range(21,41):
+    a *= i
+    b *= i-20
+print( a//b )