**Problem 81:**

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.

131 |
673 | 234 | 103 | 18 |

201 |
96 |
342 |
965 | 150 |

630 | 803 | 746 |
422 |
111 |

537 | 699 | 497 | 121 |
956 |

805 | 732 | 524 | 37 |
331 |

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.

**Idea:**

This problem is identical to problem 18, except in the form of a matrix instead of tree, and I want the minimal path instead of maximum path. I modified the algorithm I used for problem 18 to go either right or down (instead of down, or down and to the right). Tested it out and it worked.