Given two strings s and t, each containing letters and '#' characters (representing backspace), determine if they are equal after all backspaces are applied. Google phone screens frequently include this problem to test your ability to handle string manipulation with constraints.
For example, s = "ab#c" and t = "ad#c" both become "ac", so you'd return true.
Here's where it gets interesting: you can solve this with a stack in time and space. But can you do it in space? Think about processing the strings from right to left.
Constraints: . Only lowercase letters and '#'.