initial commit

maze/recursive-backtracker-debug.js

@@ -0,0 +1,85 @@
+'use strict';
+
+import _ from '../utils';
+
+let width = parseInt(_.args[0], 10) || 10,
+    height = parseInt(_.args[1], 10) || 10;
+
+// Generate the two-dimensional array
+let grid = new Array(width);
+
+for(let i = 0; i < width; i++) {
+  grid[i] = new Array(height);
+}
+
+grid.width = width;
+grid.height = height;
+
+// define directions in bits so we can use bitwise flags
+// to merge and compare
+// left 1 right 2
+// top 4 bottom 8
+let directions = [1, 2, 4, 8];
+let opposite = {
+  1: 2,
+  2: 1,
+  4: 8,
+  8: 4
+};
+
+// Used to sort randomly
+const randomSort = () =>
+  Math.random() > 0.5 ? 1 : -1;
+
+function walker(cx, cy, grid) {
+  _.debug(`walker running for ${cx}, ${cy}`);
+
+  let destination = directions.sort(randomSort);
+
+  destination.forEach(function(dir) {
+  _.debug(` - direction: ${dir}`);
+
+    // find the next block
+    let nx = cx + (dir === 1 ? -1 : dir === 2 ? 1 : 0),
+        ny = cy + (dir === 4 ? -1 : dir === 8 ? 1 : 0);
+
+    _.debug(` - trying next block nx=${nx} ny=${ny}`);
+
+    // Make sure the next block is in grid and we haven't visited it before
+    if(nx < grid.width && nx >= 0 && ny < grid.height && ny >= 0 && !grid[nx][ny]) {
+      _.debug(` - ${grid[cx][cy]} |= ${dir}`);
+      _.debug(` - ${grid[nx][ny]} |= ${opposite[dir]}`);
+      grid[cx][cy] |= dir;
+      grid[nx][ny]  = opposite[dir];
+
+      walker(nx, ny, grid);
+    }
+  });
+}
+
+walker(0, 0, grid);
+
+_.debug(grid);
+
+function draw(grid) {
+  _.log('  ' + '_'.repeat(grid.width*2 - 1));
+
+  for(let i = 0; i < grid.width; i++) {
+    _.print('|');
+    for(let j = 0; j < grid.height; j++) {
+      let c = grid[i][j];
+
+      // bottom lines
+      if((c & 8) === 0) _.print(" ");
+      else _.print("_");
+
+      // right lines
+      if((c & 2) === 0) _.print(" ");
+      else _.print("|");
+    }
+    _.print('|');
+    _.print('\n');
+  }
+}
+
+draw(grid);

maze/recursive-backtracker.js

@@ -0,0 +1,75 @@
+'use strict';
+
+import _ from '../utils';
+
+let width = parseInt(_.args[0], 10) || 10,
+    height = parseInt(_.args[1], 10) || 10;
+
+// Generate the two-dimensional array
+let grid = new Array(width);
+
+for(let i = 0; i < width; i++) {
+  grid[i] = new Array(height);
+}
+
+grid.width = width;
+grid.height = height;
+
+// define directions in bits so we can use bitwise flags
+// to merge and compare
+// left 1 right 2
+// top 4 bottom 8
+let directions = [1, 2, 4, 8];
+let opposite = {
+  1: 2,
+  2: 1,
+  4: 8,
+  8: 4
+};
+
+// Used to sort randomly
+const randomSort = () =>
+  Math.random() > 0.5 ? 1 : -1;
+
+function walker(cx, cy, grid) {
+  let destination = directions.sort(randomSort);
+
+  destination.forEach(function(dir) {
+    // find the next block
+    let nx = cx + (dir === 1 ? -1 : dir === 2 ? 1 : 0),
+        ny = cy + (dir === 4 ? -1 : dir === 8 ? 1 : 0);
+
+    // Make sure the next block is in grid and we haven't visited it before
+    if(nx < grid.width && nx >= 0 && ny < grid.height && ny >= 0 && !grid[nx][ny]) {
+      grid[cx][cy] |= dir;
+      grid[nx][ny]  = opposite[dir];
+
+      walker(nx, ny, grid);
+    }
+  });
+}
+
+walker(0, 0, grid);
+
+function draw(grid) {
+  _.log('  ' + '_'.repeat(grid.width*2 - 1));
+
+  for(let i = 0; i < grid.width; i++) {
+    _.print('|');
+    for(let j = 0; j < grid.height; j++) {
+      let c = grid[i][j];
+
+      // bottom lines
+      if((c & 8) === 0) _.print(" ");
+      else _.print("_");
+
+      // right lines
+      if((c & 2) === 0) _.print(" ");
+      else _.print("|");
+    }
+    _.print('|');
+    _.print('\n');
+  }
+}
+
+draw(grid);