Project Euler — Problem 81 Solution

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…

Project Euler — Problem 99 Solution

Problem

Comparing two numbers written in index form like 211 and 37 is not difficult, as any calculator would confirm that 211 = 2048 < 37 = 2187.

However, confirming that 632382518061 > 519432525806 would be…

Project Euler — Problem 205 Solution

Problem

Peter has nine four-sided (pyramidal) dice, each with faces numbered 1, 2, 3, 4.
Colin has six six-sided (cubic) dice, each with faces numbered 1, 2, 3, 4, 5, 6.

Peter and Colin roll their dice and…

Project Euler — Problem 85

Problem

By counting carefully it can be seen that a rectangular grid measuring 3 by 2 contains eighteen rectangles: