07.1
Sudoku
Random valid puzzle · hint tool · animated backtracking solver. back to widgets
$sudoku --new --difficulty medium
>32 givens loaded · 81 cells · click a cell, type 1-9
why this exists
I built this because I bombed the Sudoku Solver question (LeetCode 37) in an interview. Keeping it on the site as a reminder — and so the backtracking pattern stays in muscle memory. Use the auto-solve tool below to watch the same algorithm I should have written, run cell-by-cell.filled: 32/81|conflicts: 0|given: 32|moves: 0
game
difficulty:
tools
// hint — for the selected cell, lists every digit 1-9 that satisfies the row/column/box rules right now.
// auto solve — runs backtracking. If your entries don't lead to a valid solution, they'll be cleared and the search restarts from the givens.
// show solution — fills the board with the canonical answer instantly.
// indicators — toggles the row / column / 3x3 box and same-value highlights for the selected cell.
solver
state: idle
2 ms · fastest50 ms · slow
amber = trying a digit
mint = committed
red = backtracking