2016 Update

Task/Flipping-bits-game/JavaScript/flipping-bits-game.js

@@ -0,0 +1,96 @@
+function numOfRows(board) { return board.length; }
+function numOfCols(board) { return board[0].length; }
+function boardToString(board) {
+    // First the top-header
+    var header = '   ';
+    for (var c = 0; c < numOfCols(board); c++)
+        header += c + ' ';
+
+    // Then the side-header + board
+    var sideboard = [];
+    for (var r = 0; r < numOfRows(board); r++) {
+        sideboard.push(r + ' [' + board[r].join(' ') + ']');
+    }
+
+    return header + '\n' + sideboard.join('\n');
+}
+function flipRow(board, row) {
+    for (var c = 0; c < numOfCols(board); c++) {
+        board[row][c] = 1 - board[row][c];
+    }
+}
+function flipCol(board, col) {
+    for (var r = 0; r < numOfRows(board); r++) {
+        board[r][col] = 1 - board[r][col];
+    }
+}
+
+function playFlippingBitsGame(rows, cols) {
+    rows = rows | 3;
+    cols = cols | 3;
+    var targetBoard = [];
+    var manipulatedBoard = [];
+    // Randomly generate two identical boards.
+    for (var r = 0; r < rows; r++) {
+        targetBoard.push([]);
+        manipulatedBoard.push([]);
+        for (var c = 0; c < cols; c++) {
+            targetBoard[r].push(Math.floor(Math.random() * 2));
+            manipulatedBoard[r].push(targetBoard[r][c]);
+        }
+    }
+    // Naive-scramble one of the boards.
+    while (boardToString(targetBoard) == boardToString(manipulatedBoard)) {
+        var scrambles = rows * cols;
+        while (scrambles-- > 0) {
+            if (0 == Math.floor(Math.random() * 2)) {
+                flipRow(manipulatedBoard, Math.floor(Math.random() * rows));
+            }
+            else {
+                flipCol(manipulatedBoard, Math.floor(Math.random() * cols));
+            }
+        }
+    }
+    // Get the user to solve.
+    alert(
+        'Try to match both boards.\n' +
+        'Enter `r<num>` or `c<num>` to manipulate a row or col or enter `q` to quit.'
+        );
+    var input = '', letter, num, moves = 0;
+    while (boardToString(targetBoard) != boardToString(manipulatedBoard) && input != 'q') {
+        input = prompt(
+            'Target:\n' + boardToString(targetBoard) +
+            '\n\n\n' +
+            'Board:\n' + boardToString(manipulatedBoard)
+            );
+        try {
+            letter = input.charAt(0);
+            num = parseInt(input.slice(1));
+            if (letter == 'q')
+				break;
+            if (isNaN(num)
+                || (letter != 'r' && letter != 'c')
+                || (letter == 'r' && num >= rows)
+                || (letter == 'c' && num >= cols)
+                ) {
+                throw new Error('');
+            }
+            if (letter == 'r') {
+                flipRow(manipulatedBoard, num);
+            }
+            else {
+                flipCol(manipulatedBoard, num);
+            }
+            moves++;
+        }
+        catch(e) {
+            alert('Uh-oh, there seems to have been an input error');
+        }
+    }
+    if (input == 'q') {
+        alert('~~ Thanks for playing ~~');
+    }
+    else {
+        alert('Completed in ' + moves + ' moves.');
+    }
+}