1 files changed, 35 insertions, 0 deletions
diff --git a/src/lib/sudoku/solve.ts b/src/lib/sudoku/solve.ts
new file mode 100644
index 0000000..eedb576
--- /dev/null
+++ b/src/lib/sudoku/solve.ts
@@ -0,0 +1,35 @@
+function solve() {
+  let board = self.readBoard(true);
+  let backtrack = 0;
+  let guesswork = 0;
+  let dcount = 0;
+  let time = Date.now();
+  if (solve()) {
+    stats();
+    self.writeBytes(board);
+    el.classList.add("solved");
+  } else {
+    stats();
+    alert("no solution");
+  }
+  function solve() {
+    let { index, moves, len } = analyze(board);
+    if (index == null) return true;
+    if (len > 1) guesswork++;
+    for (let m = 1; moves; m <<= 1) {
+      if (moves & m) {
+        dcount++;
+        board[index] = m;
+        if (solve()) return true;
+        moves ^= m;
+      }
+    }
+    board[index] = 0;
+    ++backtrack;
+    return false;
+  }
+  function stats() {
+    log(el, `${dcount} digits placed<br>${backtrack} take-backs<br>${guesswork} guesses<br>${Date.now() - time} milliseconds`);
+  }
+}
+