March 2014 update

Task/100-doors/JavaScript/100-doors-2.js

@@ -1,19 +1,9 @@
-var
- n = 100,
- doors = [n],
- step,
- idx;
-// now, start opening and closing
-for (step = 1; step <= n; step += 1)
- for (idx = step; idx <= n; idx += step)
- // toggle state of door
- doors[idx] = !doors[idx];
+Array.apply(null, { length: 100 })
+  .map(function(v, i) { return i + 1; })
+    .forEach(function(door) {
+      var sqrt = Math.sqrt(door);
 
-// find out which doors are open
-var open = doors.reduce(function(open, val, idx) {
-    if (val) {
-        open.push(idx);
-    }
-    return open;
-}, []);
-document.write("These doors are open: " + open.join(', '));
+      if (sqrt === (sqrt | 0)) {
+        console.log("Door %d is open", door);
+      }
+    });