problem36

Problem 36: Double-base palindromes

Problem statement

The decimal number, 585 = 1001001001₂ (binary), is palindromic in both bases.

Find the sum of all numbers, less than one million, which are palindromic in base 10 and base 2.

(Please note that the palindromic number, in either base, may not include leading zeros.)

Comments

The only question here is what the easiest/fastest way to check for palindromes is. I suppose I can speed things up slightly by ignoring all even numbers, as those can't be base-2 palindromes.

Though actually... what if I built up the numeric value in one base so as to be an (odd) palindrome, and then checked the number to see whether it were also a palindrome in the other base? That would likely mean visiting the palindromes out of order, but all I care about is their sum.

...

Well, I think that's a good algorithmic idea, but my attempt to code it rust failed miserably. Going to go ask the rust community in discord.

...

The rust people on discord taught me a bit about &dyn, but the real mistake I was making was in not using a reference in the first place.

This problem wound up having the same algorithm in both rust and python, because I debugged my algorithm in python while I was unable to get it to compile in rust.