Project euler problem 67.

ProjectEuler/p067_MaximumPathSumII.py

@@ -1,30 +1,34 @@
-/* Check cf5-opt.vim defs.
-VIM: let g:lcppflags="-std=c++11 -O2 -pthread"
-VIM: let g:wcppflags="/O2 /EHsc /DWIN32"
-VIM: let g:argv=""
-VIM-: let g:cf5output=0
-*/
-#include <iostream>
-#include <exception>
+#Maximum path sum II
+#Problem 67
+#
+#By starting at the top of the triangle below and moving to adjacent numbers on
+#the row below, the maximum total from top to bottom is 23.
+#
+#3
+#7 4
+#2 4 6
+#8 5 9 3
+#
+#That is, 3 + 7 + 4 + 9 = 23.
+#
+#Find the maximum total from top to bottom in triangle.txt (right click and 
+#'Save Link/Target As...'), a 15K text file containing a triangle with
+#one-hundred rows.
+#
+#NOTE: This is a much more difficult version of Problem 18. It is not possible
+#to try every route to solve this problem, as there are 299 altogether! If you
+#could check one trillion (1012) routes every second it would take over twenty
+#billion years to check them all. There is an efficient algorithm to solve it. ;o)
 
-/*
-*/
+f = open( "p067_triangle.txt", "r" )
+a = [[ int(n) for n in line.split(' ') ] for line in f]
+
+for i in reversed(range(0,len(a)-1)):
+    for j in range(0,len(a[i])):
+        a[i][j] += max(a[i+1][j],a[i+1][j+1])
+
+
+print(a[0][0])
 
-int main ( void )
-{try{
 
-	return 0;
-}
-catch ( const std::exception& e )
-{
-	std::cerr << std::endl
-			<< "std::exception(\"" << e.what() << "\")." << std::endl;
-	return 2;
-}
-catch ( ... )
-{
-	std::cerr  << std::endl
-			<< "unknown exception." << std::endl;
-	return 1;
-}}