sudoku.js Example File

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  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the QtScxml module of the Qt Toolkit.
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  function restart() {
      for (var i = 0; i < initState.length; i++)
          currentState[i] = initState[i].slice();
      undoStack = [];
  }

  function isValidPosition() {
      var x = _event.data.x;
      var y = _event.data.y;
      if (x < 0 || x >= initState.length)
          return false;
      if (y < 0 || y >= initState.length)
          return false;
      if (initState[x][y] !== 0)
          return false;
      return true;
  }

  function calculateCurrentState() {
      if (isValidPosition() === false)
          return;
      var x = _event.data.x;
      var y = _event.data.y;
      var currentValue = currentState[x][y];
      if (currentValue === initState.length)
          currentValue = 0;
      else
          currentValue += 1;
      currentState[x][y] = currentValue;
      undoStack.push([x, y]);
  }

  function isOK(numbers) {
      var temp = [];
      for (var i = 0; i < numbers.length; i++) {
          var currentValue = numbers[i];
          if (currentValue === 0)
              return false;
          if (temp.indexOf(currentValue) >= 0)
              return false;
          temp.push(currentValue);
      }
      return true;
  }

  function isSolved() {
      for (var i = 0; i < currentState.length; i++) {
          if (!isOK(currentState[i]))
              return false;

          var column = [];
          var square = [];
          for (var j = 0; j < currentState[i].length; j++) {
              column.push(currentState[j][i]);
              square.push(currentState[Math.floor(i / 3) * 3 + Math.floor(j / 3)]
                                      [i % 3 * 3 + j % 3]);
          }

          if (!isOK(column))
              return false;
          if (!isOK(square))
              return false;
      }
      return true;
  }

  function undo() {
      if (!undoStack.length)
          return;

      var lastMove = undoStack.pop();
      var x = lastMove[0];
      var y = lastMove[1];
      var currentValue = currentState[x][y];
      if (currentValue === 0)
          currentValue = initState.length;
      else
          currentValue -= 1;
      currentState[x][y] = currentValue;
  }