@@ -0,0 +1,26 @@
+/**
+ * @param {string} a
+ * @param {string} b
+ * @return {string}
+ */
+var addBinary = function(a, b) {
+    
+    var maxlength = Math.max(a.length, b.length);
+    a = a.padStart(maxlength, '0');
+    b = b.padStart(maxlength, '0');
+    
+    var n = a.length
+    var res = "";
+    var sum = 0;
+    var carry = 0;
+    for (var i = n-1; i >= 0; i--) {
+        var aBit = Number(a[i]);
+        var bBit = Number(b[i]);
+        var sum = aBit ^ bBit ^ carry;
+        carry = (aBit & bBit) ^ (carry & (a[i] ^ b[i]));
+        res += sum.toString();
+    }
+    if (carry == 1)
+        res += '1';
+    return res.split("").reverse("").join("");
+};