Given a list of ranges (inclusive) and a list of IDs, how many of the IDs are in any range?

Given a grid of solid @ and empty cells ., count how many solid cells have less than 4 neighbors.

Given a list of numbers, for each find the two digits in the number which if concatenated make the largest. Sum these values.

For example: 811111111111119 should be 89.

Given a list of ranges a-b (ie 11-22), sum all values that are made of two repeated chunks of digits (ie 123123)

Implement a padlock with 100 values (0-99). Run each command (L23 to turn left by 23 places) and then output the number of times you landed on zero.