From 44ff6231441024d16fddc2b7cb648539522b04cb Mon Sep 17 00:00:00 2001
From: Maksymilian Jopek <maks@jopek.eu>
Date: Mon, 19 Dec 2022 21:04:23 +0100
Subject: v1.0.0 Added everything that's in the spec

---
 src/lib/bestest.js | 555 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 555 insertions(+)
 create mode 100644 src/lib/bestest.js

(limited to 'src/lib/bestest.js')

diff --git a/src/lib/bestest.js b/src/lib/bestest.js
new file mode 100644
index 0000000..6ff9196
--- /dev/null
+++ b/src/lib/bestest.js
@@ -0,0 +1,555 @@
+class Sudoku {
+  constructor(container, { controls = true, pauseOnGuess = false } = {}) {
+    this.container = container;
+    this._pauseOnGuess = pauseOnGuess;
+    this.init(controls);
+
+    if (controls) {
+      container.querySelector(".js-examples-select").addEventListener("change", ev => {
+        this.writeBoard(ev.target.value.split(",").map(parseFloat), true);
+      });
+      container.querySelector(".js-examples-select").addEventListener("click", ev => {
+        this.writeBoard(ev.target.value.split(",").map(parseFloat), true);
+      });
+      container.querySelector(".js-solve").addEventListener("click", ev => this.solve());
+      container.querySelector(".js-play").addEventListener("click", ev => this.stepSolve());
+      container.querySelector(".js-pause").addEventListener("click", ev => this.pause());
+      container.querySelector(".js-continue").addEventListener("click", ev => this.continue());
+      container.querySelector(".js-reset").addEventListener("click", ev => this.reset());
+      container.querySelector(".js-clear").addEventListener("click", ev => this.clearBoard());
+    }
+  }
+
+  init(controls = true) {
+    let container = this.container;
+    let html = `\
+  <div class="sudoku">
+    <div class="sudoku-board">
+      ${[...Array(81).keys()].map(i => {
+      let { row, col } = i2rc(i);
+      return `<input class="js-field" maxlength="1" type="text" data-index="${i}" data-row="${row}" data-col="${col}" />`;
+    }).join("")}
+    </div>
+    <div class="controls">
+    ${!controls ? '' : `
+        <select class="js-examples-select">
+          <option selected disabled hidden>Examples</option>
+          ${examples.map(example => `
+              <option value="${example.slice(1).join(",")}">${example[0]}</option>
+            `).join("")}
+        </select>
+        <button class="js-solve">Solve!</button>
+        <button class="js-play">Play</button>
+        <button class="js-pause">Pause</button>
+        <button class="js-continue">Continue</button>
+        <button class="js-reset">Reset</button>
+        <button class="js-clear">Clear</button>`}
+      <div class="stats js-console"></div>
+    </div>
+  </div>`;
+    container.innerHTML = html;
+    let fields = container.querySelectorAll("input.js-field");
+    fields.forEach(input => {
+      input.addEventListener("click", ev => {
+        input.focus();
+        input.select();
+      });
+      input.addEventListener("focus", ev => {
+        let index = +input.dataset.index;
+        log(container, `Allowed digits:
+      ${b2ds(analyze(this.readBoard()).allowed[index]).join(", ")}`);
+      });
+      input.addEventListener("keydown", ev => {
+        let idx = +input.dataset.index;
+        if (ev.keyCode >= 48 && ev.keyCode <= 57) {
+          input.value = String.fromCharCode(ev.keyCode);
+          if (input.value == "0") input.value = "";
+          input.select();
+          ev.preventDefault();
+        } else {
+          let parent = input.parentNode;
+          let next;
+          switch (ev.keyCode) {
+            case 38: // ↑
+              next = idx - 9; break;
+            case 40: // ↓
+              next = idx + 9; break;
+            case 39: // →
+              next = idx + 1; break;
+            case 37: // ←
+              next = idx - 1; break;
+          }
+          if (next != null) {
+            if (next < 0) next += 81;
+            next %= 81;
+            next = parent.querySelector(`input[data-index="${next}"]`);
+            next.focus();
+            next.select();
+            ev.preventDefault();
+          }
+        }
+      });
+    });
+  }
+
+  pause() {
+    clearTimeout(this._playTimer);
+    this.container.classList.add("paused");
+  }
+
+  continue() {
+    this.container.classList.remove("paused");
+    this._playCont();
+  }
+
+  readBoard(init = false) {
+    return [...this.container.querySelectorAll("input.js-field")]
+      .map(el => {
+        if (init) el.classList.toggle("init", el.value);
+        return el.value ? d2b(parseInt(el.value, 10)) : 0;
+      });
+  }
+
+  writeBoard(values, init = false) {
+    let el = this.container;
+    [...el.querySelectorAll("input.js-field")].forEach((el, i) => {
+      el.value = values[i] || "";
+      el.classList.remove("current");
+      if (init) {
+        el.classList.toggle("init", values[i]);
+      }
+    });
+    if (init) {
+      this._initBoard = values;
+      this._reset();
+    }
+  }
+
+  writeBytes(values, init = false) {
+    this.writeBoard(values.map(b2d), init);
+  }
+
+  clearBoard() {
+    let el = this.container;
+    [...el.querySelectorAll("input.js-field")].forEach(el => {
+      el.value = "";
+      el.classList.remove("init");
+    });
+    this._reset();
+  }
+
+  reset() {
+    this.writeBoard(this._initBoard || [], true);
+  }
+
+  _reset() {
+    let el = this.container;
+    clearTimeout(this._playTimer);
+    el.classList.remove("solved", "playing", "paused");
+    log(el, "");
+  }
+
+  solve() {
+    let self = this;
+    let el = self.container;
+    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`);
+    }
+  }
+
+  stepSolve() {
+    let self = this;
+    let el = self.container;
+    el.classList.add("playing");
+    let board = self.readBoard(true);
+    let backtrack = 0;
+    let guesswork = 0;
+    let dcount = 0;
+    solve(success => {
+      log(el, `${backtrack} take-backs<br>${guesswork} guesses`);
+      el.classList.remove("playing");
+      if (success) {
+        self.writeBytes(board);
+        el.classList.add("solved");
+      } else {
+        alert("no solution");
+      }
+    });
+    function solve(cb) {
+      let { index, moves, len } = analyze(board);
+      if (index == null) return cb(true);
+      if (self._pauseOnGuess) {
+        el.querySelector(`input[data-index="${index}"]`).classList.add("current");
+      }
+      if (len > 1) {
+        guesswork++;
+        if (self._pauseOnGuess) {
+          self._playCont = () => loop(moves, 1);
+          stats();
+          self.pause();
+          return;
+        }
+      }
+      function loop(moves, m) {
+        if (!moves) {
+          board[index] = 0;
+          ++backtrack;
+          stats();
+          cb(false);
+        } else if (moves & m) {
+          dcount++;
+          stats();
+          board[index] = m;
+          self.writeBytes(board);
+          el.querySelector(`input[data-index="${index}"]`).classList.add("current");
+          self._playTimer = setTimeout(self._playCont = () =>
+            solve(success => success ? cb(true) : loop(moves ^ m, m << 1)), 100);
+        } else loop(moves, m << 1);
+      };
+      loop(moves, 1);
+    }
+    function stats() {
+      log(el, `${dcount} digits placed<br>${backtrack} take-backs<br>${guesswork} guesses`);
+    }
+  }
+}
+
+function i2rc(index) {
+  return { row: index / 9 | 0, col: index % 9 };
+}
+
+function rc2i(row, col) {
+  return row * 9 + col;
+}
+
+function d2b(digit) {
+  return 1 << (digit - 1);
+}
+
+function b2d(byte) {
+  for (var i = 0; byte; byte >>= 1, i++);
+  return i;
+}
+
+function b2ds(byte) {
+  let digits = [];
+  for (let i = 1; byte; byte >>= 1, i++)
+    if (byte & 1) digits.push(i);
+  return digits;
+}
+
+function log(el, txt) {
+  let out = el.querySelector(".js-console");
+  if (out)
+    out.innerHTML = txt;
+}
+
+function getMoves(board, index) {
+  let { row, col } = i2rc(index);
+  let r1 = 3 * (row / 3 | 0);
+  let c1 = 3 * (col / 3 | 0);
+  let moves = 0;
+  for (let r = r1, i = 0; r < r1 + 3; r++) {
+    for (let c = c1; c < c1 + 3; c++, i++) {
+      moves |= board[rc2i(r, c)]
+        | board[rc2i(row, i)]
+        | board[rc2i(i, col)];
+    }
+  }
+  return moves ^ 511;
+}
+
+function unique(allowed, index, value) {
+  let { row, col } = i2rc(index);
+  let r1 = 3 * (row / 3 | 0);
+  let c1 = 3 * (col / 3 | 0);
+  let ir = 9 * row;
+  let ic = col;
+  let uniq_row = true, uniq_col = true, uniq_3x3 = true;
+  for (let r = r1; r < r1 + 3; ++r) {
+    for (let c = c1; c < c1 + 3; ++c, ++ir, ic += 9) {
+      if (uniq_3x3) {
+        let i = rc2i(r, c);
+        if (i != index && allowed[i] & value) uniq_3x3 = false;
+      }
+      if (uniq_row) {
+        if (ir != index && allowed[ir] & value) uniq_row = false;
+      }
+      if (uniq_col) {
+        if (ic != index && allowed[ic] & value) uniq_col = false;
+      }
+      if (!(uniq_3x3 || uniq_row || uniq_col)) return false;
+    }
+  }
+  return uniq_row || uniq_col || uniq_3x3;
+}
+
+function analyze(board) {
+  let allowed = board.map((x, i) => x ? 0 : getMoves(board, i));
+  let bestIndex, bestLen = 100;
+  for (let i = 0; i < 81; i++) if (!board[i]) {
+    let moves = allowed[i];
+    let len = 0;
+    for (let m = 1; moves; m <<= 1) if (moves & m) {
+      ++len;
+      if (unique(allowed, i, m)) {
+        allowed[i] = m;
+        len = 1;
+        break;
+      }
+      moves ^= m;
+    }
+    if (len < bestLen) {
+      bestLen = len;
+      bestIndex = i;
+      if (!bestLen) break;
+    }
+  }
+  return {
+    index: bestIndex,
+    moves: allowed[bestIndex],
+    len: bestLen,
+    allowed: allowed
+  };
+}
+
+const examples = [
+  ["Medium 1",
+    0, 0, 0, 0, 0, 0, 0, 0, 6,
+    0, 3, 0, 0, 7, 1, 0, 4, 0,
+    0, 0, 0, 0, 0, 0, 8, 0, 0,
+
+    0, 0, 0, 9, 0, 8, 0, 7, 1,
+    1, 0, 3, 0, 0, 0, 0, 0, 0,
+    0, 0, 2, 0, 3, 0, 9, 0, 0,
+
+    5, 0, 7, 0, 0, 6, 0, 0, 0,
+    2, 0, 0, 0, 0, 0, 7, 0, 0,
+    0, 0, 1, 8, 0, 0, 0, 0, 2,
+  ],
+  ["Medium 2",
+    0, 0, 0, 0, 1, 7, 2, 0, 0,
+    0, 0, 0, 4, 0, 0, 0, 0, 0,
+    0, 0, 9, 0, 0, 3, 0, 0, 0,
+
+    4, 0, 0, 7, 8, 0, 5, 0, 0,
+    0, 2, 5, 0, 0, 0, 8, 0, 0,
+    0, 0, 0, 6, 0, 0, 0, 0, 0,
+
+    6, 0, 1, 5, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 6, 0, 3, 0,
+    2, 0, 0, 0, 0, 1, 7, 0, 4,
+  ],
+  ["Medium 3",
+    9, 0, 0, 5, 0, 1, 7, 0, 0,
+    2, 0, 1, 0, 0, 9, 0, 0, 0,
+    0, 0, 0, 8, 7, 0, 0, 9, 0,
+
+    0, 8, 0, 0, 6, 4, 0, 7, 0,
+    0, 0, 0, 0, 0, 0, 2, 1, 0,
+    0, 0, 0, 0, 9, 0, 0, 0, 0,
+
+    7, 0, 6, 2, 4, 0, 0, 0, 0,
+    0, 4, 0, 0, 0, 0, 0, 0, 6,
+    1, 0, 0, 0, 0, 0, 0, 4, 0,
+  ],
+  ["Medium 4",
+    0, 0, 0, 0, 3, 0, 5, 7, 0,
+    0, 0, 2, 0, 0, 8, 0, 0, 0,
+    6, 0, 0, 0, 0, 0, 0, 0, 0,
+
+    0, 3, 0, 5, 7, 0, 0, 4, 0,
+    0, 0, 0, 4, 0, 0, 0, 0, 2,
+    0, 0, 5, 6, 0, 0, 7, 1, 8,
+
+    0, 7, 8, 0, 0, 0, 0, 0, 0,
+    0, 0, 6, 7, 0, 9, 0, 0, 1,
+    0, 0, 0, 0, 0, 0, 0, 2, 0,
+  ],
+  ["Hard",
+    8, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 3, 6, 0, 0, 0, 0, 0,
+    0, 7, 0, 0, 9, 0, 2, 0, 0,
+
+    0, 5, 0, 0, 0, 7, 0, 0, 0,
+    0, 0, 0, 0, 4, 5, 7, 0, 0,
+    0, 0, 0, 1, 0, 0, 0, 3, 0,
+
+    0, 0, 1, 0, 0, 0, 0, 6, 8,
+    0, 0, 8, 5, 0, 0, 0, 1, 0,
+    0, 9, 0, 0, 0, 0, 4, 0, 0,
+  ],
+  ["Harder",
+    0, 0, 3, 9, 0, 0, 0, 0, 0,
+    4, 0, 0, 0, 8, 0, 0, 3, 6,
+    0, 0, 8, 0, 0, 0, 1, 0, 0,
+
+    0, 4, 0, 0, 6, 0, 0, 7, 3,
+    8, 0, 0, 0, 0, 0, 0, 1, 0,
+    0, 0, 0, 0, 0, 2, 0, 0, 0,
+
+    0, 0, 4, 0, 7, 0, 0, 6, 8,
+    6, 0, 0, 0, 0, 0, 0, 0, 0,
+    7, 0, 0, 0, 0, 0, 5, 0, 0,
+  ],
+  ["Really Hard™ — not quite",
+    0, 0, 0, 8, 0, 1, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 4, 3,
+    5, 0, 0, 0, 0, 0, 0, 0, 0,
+
+    0, 0, 0, 0, 7, 0, 8, 0, 0,
+    0, 0, 0, 0, 0, 0, 1, 0, 0,
+    0, 2, 0, 0, 3, 0, 0, 0, 0,
+
+    6, 0, 0, 0, 0, 0, 0, 7, 5,
+    0, 0, 3, 4, 0, 0, 0, 0, 0,
+    0, 0, 0, 2, 0, 0, 6, 0, 0,
+  ],
+  ["tmp2",
+    0, 0, 0, 7, 4, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 5, 0, 0, 0,
+    0, 1, 0, 0, 0, 0, 0, 0, 5,
+
+    3, 0, 0, 2, 0, 0, 0, 0, 0,
+    0, 2, 8, 0, 0, 0, 0, 5, 4,
+    0, 0, 5, 0, 6, 0, 8, 9, 0,
+
+    4, 3, 0, 9, 0, 7, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 6,
+    8, 0, 0, 0, 0, 2, 0, 3, 0,
+  ],
+  ["tmp3",
+    0, 0, 0, 0, 0, 6, 0, 8, 5,
+    0, 0, 3, 0, 0, 0, 9, 0, 7,
+    0, 1, 0, 0, 4, 0, 0, 0, 0,
+
+    1, 8, 0, 9, 0, 0, 0, 0, 0,
+    0, 0, 7, 0, 0, 0, 3, 0, 0,
+    0, 4, 0, 0, 0, 0, 0, 0, 0,
+
+    8, 0, 0, 7, 6, 0, 0, 3, 0,
+    0, 0, 0, 0, 0, 1, 0, 0, 9,
+    0, 0, 0, 0, 9, 4, 2, 0, 0,
+  ],
+  ["tmp4",
+    0, 0, 0, 0, 0, 0, 5, 2, 8,
+    4, 7, 0, 0, 1, 0, 0, 0, 0,
+    0, 0, 3, 8, 0, 0, 0, 0, 0,
+
+    0, 0, 1, 7, 8, 0, 0, 0, 3,
+    0, 0, 0, 0, 0, 0, 0, 9, 0,
+    0, 0, 0, 0, 4, 0, 0, 0, 1,
+
+    0, 0, 0, 9, 5, 8, 7, 0, 0,
+    5, 0, 0, 0, 0, 3, 0, 0, 0,
+    0, 2, 0, 0, 0, 0, 6, 0, 0,
+  ],
+  ["tmp5",
+    0, 0, 0, 0, 0, 0, 4, 0, 3,
+    0, 0, 0, 6, 0, 0, 0, 0, 0,
+    0, 0, 0, 8, 0, 0, 0, 0, 0,
+
+    0, 0, 0, 9, 0, 0, 0, 8, 0,
+    0, 2, 0, 0, 0, 0, 0, 9, 0,
+    0, 7, 0, 0, 1, 0, 0, 0, 0,
+
+    5, 0, 0, 0, 4, 0, 1, 0, 0,
+    8, 0, 0, 0, 0, 0, 3, 0, 0,
+    9, 0, 6, 0, 0, 0, 0, 0, 0,
+  ],
+  ["tmp6",
+    0, 0, 0, 0, 7, 0, 8, 0, 0,
+    6, 0, 0, 0, 0, 0, 0, 0, 3,
+    0, 0, 0, 0, 0, 0, 5, 0, 0,
+
+    5, 0, 0, 3, 0, 0, 1, 0, 0,
+    9, 0, 0, 6, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 9, 0, 0, 0,
+
+    0, 4, 7, 0, 0, 0, 0, 9, 0,
+    0, 8, 0, 0, 1, 0, 0, 0, 0,
+    0, 0, 0, 5, 0, 0, 0, 0, 0,
+  ],
+  ["tmp7",
+    0, 8, 0, 0, 0, 0, 5, 0, 0,
+    9, 0, 0, 3, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0,
+
+    0, 5, 0, 0, 4, 0, 8, 0, 0,
+    0, 0, 0, 7, 0, 0, 0, 3, 0,
+    6, 1, 0, 0, 0, 0, 0, 0, 0,
+
+    0, 0, 0, 0, 5, 0, 1, 0, 0,
+    3, 0, 0, 9, 0, 0, 0, 0, 0,
+    7, 0, 0, 0, 0, 0, 0, 0, 8,
+  ],
+  ["tmp8",
+    0, 5, 0, 0, 0, 0, 9, 3, 0,
+    4, 0, 0, 8, 0, 0, 2, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0,
+
+    0, 2, 0, 0, 0, 3, 0, 0, 0,
+    0, 0, 0, 0, 5, 0, 0, 7, 0,
+    9, 0, 0, 0, 0, 0, 0, 0, 4,
+
+    7, 0, 6, 4, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 3, 0, 0,
+    0, 0, 0, 7, 0, 0, 0, 0, 0,
+  ],
+  ["tmp9",
+    0, 0, 0, 0, 0, 0, 0, 8, 3,
+    0, 9, 0, 1, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0,
+
+    0, 0, 0, 0, 3, 5, 1, 0, 0,
+    8, 0, 0, 0, 7, 0, 0, 0, 0,
+    0, 6, 0, 0, 0, 0, 9, 0, 0,
+
+    0, 0, 0, 6, 0, 0, 4, 9, 0,
+    3, 0, 0, 4, 0, 0, 0, 0, 0,
+    7, 0, 0, 0, 0, 0, 0, 0, 0,
+  ],
+  ["tmp10",
+    0, 0, 0, 0, 4, 0, 6, 9, 0,
+    3, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 5, 0, 0,
+
+    0, 0, 0, 5, 0, 1, 0, 0, 8,
+    0, 0, 7, 3, 0, 0, 0, 0, 0,
+    0, 4, 0, 0, 0, 0, 9, 0, 0,
+
+    1, 0, 0, 0, 0, 0, 0, 0, 3,
+    0, 9, 0, 0, 0, 0, 0, 7, 0,
+    0, 0, 0, 8, 0, 0, 0, 0, 0,
+  ],
+];
+
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