September 2017 Update

Task/Maze-solving/JavaScript/maze-solving.js

@@ -0,0 +1,135 @@
+var ctx, wid, hei, cols, rows, maze, stack = [], start = {x:-1, y:-1}, end = {x:-1, y:-1}, grid = 8;
+function drawMaze() {
+    for( var i = 0; i < cols; i++ ) {
+        for( var j = 0; j < rows; j++ ) {
+            switch( maze[i][j] ) {
+                case 0: ctx.fillStyle = "black"; break;
+                case 1: ctx.fillStyle = "green"; break;
+                case 2: ctx.fillStyle = "red"; break;
+                case 3: ctx.fillStyle = "yellow"; break;
+                case 4: ctx.fillStyle = "#500000"; break;
+            }
+            ctx.fillRect( grid * i, grid * j, grid, grid  );
+        }
+    }
+}
+function getFNeighbours( sx, sy, a ) {
+    var n = [];
+    if( sx - 1 > 0 && maze[sx - 1][sy] == a ) {
+        n.push( { x:sx - 1, y:sy } );
+    }
+    if( sx + 1 < cols - 1 && maze[sx + 1][sy] == a ) {
+        n.push( { x:sx + 1, y:sy } );
+    }
+    if( sy - 1 > 0 && maze[sx][sy - 1] == a ) {
+        n.push( { x:sx, y:sy - 1 } );
+    }
+    if( sy + 1 < rows - 1 && maze[sx][sy + 1] == a ) {
+        n.push( { x:sx, y:sy + 1 } );
+    }
+    return n;
+}
+function solveMaze() {
+    if( start.x == end.x && start.y == end.y ) {
+        for( var i = 0; i < cols; i++ ) {
+            for( var j = 0; j < rows; j++ ) {
+                switch( maze[i][j] ) {
+                    case 2: maze[i][j] = 3; break;
+                    case 4: maze[i][j] = 0; break;
+                }
+            }
+        }
+        drawMaze();
+        return;
+    }
+    var neighbours = getFNeighbours( start.x, start.y, 0 );
+    if( neighbours.length ) {
+        stack.push( start );
+        start = neighbours[0];
+        maze[start.x][start.y] = 2;
+    } else {
+        maze[start.x][start.y] = 4;
+        start = stack.pop();
+    }
+
+    drawMaze();
+    requestAnimationFrame( solveMaze );
+}
+function getCursorPos( event ) {
+    var rect = this.getBoundingClientRect();
+    var x = Math.floor( ( event.clientX - rect.left ) / grid ),
+        y = Math.floor( ( event.clientY - rect.top  ) / grid );
+    if( maze[x][y] ) return;
+    if( start.x == -1 ) {
+        start = { x: x, y: y };
+    } else {
+        end = { x: x, y: y };
+        maze[start.x][start.y] = 2;
+        solveMaze();
+    }
+}
+function getNeighbours( sx, sy, a ) {
+    var n = [];
+    if( sx - 1 > 0 && maze[sx - 1][sy] == a && sx - 2 > 0 && maze[sx - 2][sy] == a ) {
+        n.push( { x:sx - 1, y:sy } ); n.push( { x:sx - 2, y:sy } );
+    }
+    if( sx + 1 < cols - 1 && maze[sx + 1][sy] == a && sx + 2 < cols - 1 && maze[sx + 2][sy] == a ) {
+        n.push( { x:sx + 1, y:sy } ); n.push( { x:sx + 2, y:sy } );
+    }
+    if( sy - 1 > 0 && maze[sx][sy - 1] == a && sy - 2 > 0 && maze[sx][sy - 2] == a ) {
+        n.push( { x:sx, y:sy - 1 } ); n.push( { x:sx, y:sy - 2 } );
+    }
+    if( sy + 1 < rows - 1 && maze[sx][sy + 1] == a && sy + 2 < rows - 1 && maze[sx][sy + 2] == a ) {
+        n.push( { x:sx, y:sy + 1 } ); n.push( { x:sx, y:sy + 2 } );
+    }
+    return n;
+}
+function createArray( c, r ) {
+    var m = new Array( c );
+    for( var i = 0; i < c; i++ ) {
+        m[i] = new Array( r );
+        for( var j = 0; j < r; j++ ) {
+            m[i][j] = 1;
+        }
+    }
+    return m;
+}
+function createMaze() {
+    var neighbours = getNeighbours( start.x, start.y, 1 ), l;
+    if( neighbours.length < 1 ) {
+        if( stack.length < 1 ) {
+            drawMaze(); stack = [];
+            start.x = start.y = -1;
+            document.getElementById( "canvas" ).addEventListener( "mousedown", getCursorPos, false );
+            return;
+        }
+        start = stack.pop();
+    } else {
+        var i = 2 * Math.floor( Math.random() * ( neighbours.length / 2 ) )
+        l = neighbours[i]; maze[l.x][l.y] = 0;
+        l = neighbours[i + 1]; maze[l.x][l.y] = 0;
+        start = l
+        stack.push( start )
+    }
+    drawMaze();
+    requestAnimationFrame( createMaze );
+}
+function createCanvas( w, h ) {
+    var canvas = document.createElement( "canvas" );
+    wid = w; hei = h;
+    canvas.width = wid; canvas.height = hei;
+    canvas.id = "canvas";
+    ctx = canvas.getContext( "2d" );
+    ctx.fillStyle = "black"; ctx.fillRect( 0, 0, wid, hei );
+    document.body.appendChild( canvas );
+}
+function init() {
+    cols = 73; rows = 53;
+    createCanvas( grid * cols, grid * rows );
+    maze = createArray( cols, rows );
+    start.x = Math.floor( Math.random() * ( cols / 2 ) );
+    start.y = Math.floor( Math.random() * ( rows / 2 ) );
+    if( !( start.x & 1 ) ) start.x++; if( !( start.y & 1 ) ) start.y++;
+    maze[start.x][start.y] = 0;
+    createMaze();
+}