Futoshiki Solver
What is the Futoshiki Solver?
Futoshiki, also known as Inequality Sudoku, is a unique logic puzzle that combines classic Sudoku rules with inequality constraints. You must fill an N×N grid with numbers (usually from 1 to N), ensuring that each number appears only once in every row and column, while also respecting the inequality signs (greater than or less than) placed between some cells.
Unlike traditional Sudoku, these inequality conditions add a new layer of challenge to the game. And for larger grids, like 9x9, solving can become even more difficult—sometimes even impossible if the puzzle contains input errors or conflicting inequalities.
To help you tackle Futoshiki puzzles more efficiently, we've developed the Futoshiki Solver. It not only checks whether a puzzle is solvable but also provides a quick solution, so you can avoid wasting time on impossible setups.
How to Use the Futoshiki Solver
- Choose a Grid Size: Start by selecting your desired grid size, from 3x3 to 9x9. Larger grids bring more complexity and more inequality constraints.
- Enter Numbers and Inequalities: Fill in the grid with numbers, making sure each number is unique within its row and column. To set inequalities, click between two cells:
- First click adds a "greater than"sign ( > )
- Second click changes it to "less than"( < )
- Third click removes the inequality.
- Click "Solve"to Generate the Answer: Once everything is set, hit the "Solve"button. If your setup is valid, the solver will fill in the correct numbers. If there are issues (like duplicate numbers or conflicting inequalities), you'll get an error message so you can make corrections.
- Click "Clear"to Start Over: Need a fresh start? Click the "Clear"button to remove all inputs and reset the grid for a new attempt.
Why Use the Futoshiki Solver?
1. Quickly Solve Complex Puzzles
Futoshiki puzzles—especially in larger formats—can be time-consuming to solve manually. The solver analyzes your inputs and delivers a valid solution almost instantly.
2. Avoid Wasting Time on Unsolvable Puzzles
Some puzzles have no solution due to input errors or flawed inequality placement. The solver checks solvability and alerts you if the puzzle is impossible to solve.
3. Easy Inequality Input
Click-based inequality entry is fast and user-friendly, making it easy to match numbers with the correct relationship and avoid errors from manual input.
4. Clean and Intuitive Interface
No complicated setup—just enter numbers, define inequalities, and click "Solve."It's simple enough for beginners but powerful enough for advanced players.
Frequently Asked Questions
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How do I input inequality signs?
Click the space between two cells:
- 1st click = "greater than"( > )
- 2nd click = "less than"( < )
- 3rd click = remove the inequality
This lets you adjust constraints quickly and accurately.
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Is the solution unique?
Some Futoshiki puzzles have a unique solution; others may have multiple valid answers. If the solver gives you a result that satisfies all constraints, it's a correct solution.
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What happens if the inequalities are set incorrectly?
If there are errors—like conflicting numbers or incorrect inequalities—the solver won't return an answer and will display a helpful error message. You can then check and correct your inputs.
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What numbers can I enter?
You can only use numbers from 1 to N, where N is the size of your grid. For example, in a 4x4 grid, valid numbers are 1 through 4. Each number must appear only once per row and column.