This problem is used in most wordster/boggle/Wordy Birdies (from the makers of Angry Birds) style games. "In the same order" is an unnecessary additional compl

This problem is used in most wordster/boggle/Wordy Birdies (from the makers of Angry Birds) style games. "In the same order" is an unnecessary additional complexity. Asking for an O(1) solution demonstrates the exact same thought quality, so it's a bad (overly complicated and longer to answer) interview question for the purpose intended.