Hanabi is NP-hard, even for cheaters who look at their cards

We introduce a single-player, perfect-information model and show that the game is intractable even for this simplified version where we forego both the hidden information and the multiplayer aspect of the game, even when the player can only hold two cards in her hand. On the positive side, we show that the decision version of the problem-to decide whether or not numbers from 1 through n can be played for every color-can be solved in (almost) linear time for some restricted cases.