diff --git a/.travis.yml b/.travis.yml
index f52bbce..c43f53f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,14 +1,17 @@
 language: node_js
 node_js:
-  - "6"
+  - "8"
+#Travis-CI Caching
+cache:
+  directories:
+    -node_modules
 
 addons:
   chrome: stable
 
-before_script:
-  - "export DISPLAY=:99.0"
-  - "sh -e /etc/init.d/xvfb start"
-  - sleep 3 # give xvfb some time to start
+dist: xenial
+services:
+  -xvfb
 
 before_install:
   npm install karma-cli -g
\ No newline at end of file
diff --git a/quz/quz.js b/quz/quz.js
index 624e7de..0c619a5 100755
--- a/quz/quz.js
+++ b/quz/quz.js
@@ -9,6 +9,17 @@
  */
 function dcate(A, B) {
 	/** Fill in here **/
+	let len = A.toString().match(/\d/g).length,
+		p = A,
+		i;
+	for(i = 0; i < len; i++) {
+		if(p.tail !== null) {
+			p = p.tail;
+		} else {
+			p.tail = B;
+		}
+	}
+	return A;
 }
 
 /**
@@ -24,4 +35,27 @@ function dcate(A, B) {
  */
 function sub(L, start, len) {
 	/** Fill in here **/
+	let length = L.toString().match(/\d/g).length,
+	p = l,
+	R = {
+		head: null,
+		tail: null
+	},
+	s = R,
+	i = 0;
+	while(i < length && i <= start + len - 1) {
+		if(i === start) {
+			R.head = p.head;
+		} else if(i > start) {
+			s.tail = {
+				head: p.head,
+				tail: null
+			}
+			s = s.tail;
+		}
+		p.tail && (p = p.tail);
+		i++;
+	}
+	R.toString = L.toString;
+	return R;
 }