Klondike Solitaire

Goal

Build the four foundations, one per suit, from the Ace up to the King.

How it works

• Seven columns: only the top card is visible; hidden cards turn face up as soon as they are uncovered.
• In the columns, you build down by one rank, alternating red and black: a black 9 on a red 10.
• An ordered run moves as a block. Only a King (or a run starting with a King) can fill an empty column.
• Tap the stock to draw: one card at the Easy to Hard levels, three cards at the Expert and Devilish levels. At the Devilish level, you can only go through the stock three times.

Controls

• Drag and drop a card or a run.
• Tap a card: it goes to the best spot, the foundation first.
• Double tap: straight to the foundation.
• Keyboard: Space to draw, Ctrl+Z to undo, I for a hint.
• When all the cards are visible, the game finishes by itself.

Classic scoring

• Stock to column: 5 points; to a foundation: 10 points; card turned over: 5 points.
• Foundation to column: minus 15 points. Recycling the stock: minus 100 points in draw-one, minus 20 points from the fourth pass in draw-three.
• Minus 2 points every 10 seconds, then a time bonus on victory (700,000 divided by the duration in seconds).

About the solver

Each deal is chosen by a solver that plays the game with the cards face up (depth-first search, automatic safe moves, transposition table), in a separate thread: it is guaranteed winnable. Difficulty is measured by the number of dead ends the solver has to explore before finding the solution. The hint queries the same solver on the current position (so it knows the order of the hidden cards). The deal number lets you replay a game exactly.