data/problems/81.yml
---
:id: 81
:name: 'Path sum: two ways'
:url: https://projecteuler.net/problem=81
:content: |+
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.
$$ \begin{pmatrix} \color{red}{131} & 673 & 234 & 103 & 18\\ \color{red}{201} & \color{red}{96} & \color{red}{342} & 965 & 150\\ 630 & 803 & \color{red}{746} & \color{red}{422} & 111\\ 537 & 699 & 497 & \color{red}{121} & 956\\ 805 & 732 & 524 & \color{red}{37} & \color{red}{331} \end{pmatrix} $$
Find the minimal path sum, in [matrix.txt](project/resources/p081_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.