From 94b2c6826736363a03443aa905ae051dda030169 Mon Sep 17 00:00:00 2001
From: beizhedenglong <2501211450@qq.com>
Date: Sun, 11 Sep 2016 23:26:57 +0800
Subject: [PATCH] fix bug in CircularLinkedList
There is a bug in insert function. If you insert an element in an empty
list at the first position. It will throw a TypeError: Cannot read
property 'next' of null.
---
chapter05/05-CircularLinkedList.js | 27 +++++++++++++++++----------
chapter05/05-CircularLinkedList2.js | 21 ++++++++++++---------
2 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/chapter05/05-CircularLinkedList.js b/chapter05/05-CircularLinkedList.js
index 5f05e85f..c3151148 100644
--- a/chapter05/05-CircularLinkedList.js
+++ b/chapter05/05-CircularLinkedList.js
@@ -46,16 +46,22 @@ function CircularLinkedList() {
index = 0;
if (position === 0){ //add on first position
-
- node.next = current;
-
- //update last element
- while(current.next !== head){ //last element will be head instead of NULL
- current = current.next;
+
+ if(!head){ // if no node in list
+ head = node;
+ node.next = head;
+ }else{
+ node.next = current;
+
+ //update last element
+ while(current.next !== head){ //last element will be head instead of NULL
+ current = current.next;
+ }
+
+ head = node;
+ current.next = head;
}
-
- head = node;
- current.next = head;
+
} else {
while (index++ < position){
@@ -180,4 +186,5 @@ function CircularLinkedList() {
this.print = function(){
console.log(this.toString());
};
-}
\ No newline at end of file
+}
+
diff --git a/chapter05/05-CircularLinkedList2.js b/chapter05/05-CircularLinkedList2.js
index 5aab62d0..6f7574ef 100644
--- a/chapter05/05-CircularLinkedList2.js
+++ b/chapter05/05-CircularLinkedList2.js
@@ -58,15 +58,18 @@ let CircularLinkedList2 = (function () {
if (position === 0) { //add on first position
- node.next = current;
-
- //update last element
- while (current.next !== this.getHead()) { //last element will be head instead of NULL
- current = current.next;
- }
-
- head.set(this, node);
- current.next = this.getHead();
+ if(!this.getHead()) { // if no node in list
+ head.set(this, node);
+ node.next = this.getHead();
+ } else {
+ node.next = current;
+ //update last element
+ while(current.next !== this.getHead()) { //last element will be head instead of NULL
+ current = current.next;
+ }
+ head.set(this, node);
+ current.next = this.getHead();
+ }
} else {
while (index++ < position) {