i was certain i had solved this one rather quickly, but i get the wrong answer. i am new to dynamic programming and any clues on how to debug this would be appreciated.
the problem:
In the 5 by 5 matrix below, the minimal path sum from the top left to the bottom right, by only moving to the right and down, is indicated in bold red and is equal to 2427.

Find the minimal path sum, in matrix.txt (right click and 'Save Link/Target As...'), a 31K text file containing a 80 by 80 matrix, from the top left to the bottom right by only moving right and down.

i fixed the obvious problem. i wasn't adding i was assigning. my answer is now much closer to the correct answer. i get 409646, correct answer is 427337