Count the number of ways to walk from the top-left to the bottom-right of a grid, only moving right or down.
Find the longest sequence of characters that appears in both strings (not necessarily contiguous).
Find the fewest single-character edits (insert, delete, or replace) needed to turn one word into another.
Count how many different ways you can make change for a given amount using unlimited coins of each denomination.
Assign a plus or minus sign to each number so they all add up to a target. Count the ways.
Check if a third string is a valid interleaving of two other strings, keeping the order of characters from each.