The problem I am given a string of possible digits 2 through 9. These digits are mapped to letters, like an old T9 cell phone, and I need to return all possible letter combinations that the digits can produce. I've looking into this problem for long enough...

The problem Aight, back to difficult problems. I need to find all collections of three digits in a collection that sum to zero. I feel like the first thing to do is sort the array - O(N logn) time - because we are trying to target a specific number - 0 - a...