Merge pull request #220 from flames519/master

链表：0707，0203，0206，面试题02.07 javaScript版本

problems/0203.移除链表元素.md

@@ -201,6 +201,28 @@ Python：
 
 Go：
 
+javaScript: 
+
+```js
+/**
+ * @param {ListNode} head
+ * @param {number} val
+ * @return {ListNode}
+ */
+var removeElements = function(head, val) {
+    const ret = new ListNode(0, head);
+    let cur = ret;
+    while(cur.next) {
+        if(cur.next.val === val) {
+            cur.next =  cur.next.next;
+            continue;
+        }
+        cur = cur.next;
+    }
+    return ret.next;
+};
+```
+
 
 
 

problems/0206.翻转链表.md

@@ -147,6 +147,61 @@ Python：
 
 Go：
 
+javaScript: 
+
+```js
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+
+// 双指针：
+var reverseList = function(head) {
+    if(!head || !head.next) return head;
+    let temp = null, pre = null, cur = head;
+    while(cur) {
+        temp = cur.next;
+        cur.next = pre;
+        pre = cur;
+        cur = temp;
+    }
+    // temp = cur = null;
+    return pre;
+};
+
+// 递归：
+var reverse = function(pre, head) {
+    if(!head) return pre;
+    const temp = head.next;
+    head.next = pre;
+    pre = head
+    return reverse(pre, temp);
+}
+
+var reverseList = function(head) {
+    return reverse(null, head);
+};
+
+// 递归2
+var reverse = function(head) {
+    if(!head || !head.next) return head;
+    // 从后往前翻
+    const pre = reverse(head.next);
+    head.next = pre.next;
+    pre.next = head;
+    return head;
+}
+
+var reverseList = function(head) {
+    let cur = head;
+    while(cur && cur.next) {
+        cur = cur.next;
+    }
+    reverse(head);
+    return cur;
+};
+```
+
 
 
 

problems/0707.设计链表.md

@@ -393,6 +393,142 @@ class MyLinkedList:
 
 Go：
 
+javaScript:
+
+```js
+
+class LinkNode {
+    constructor(val, next) {
+        this.val = val;
+        this.next = next;
+    }
+}
+
+/**
+ * Initialize your data structure here.
+ * 单链表 储存头尾节点 和 节点数量
+ */
+var MyLinkedList = function() {
+    this._size = 0;
+    this._tail = null;
+    this._head = null;
+};
+
+/**
+ * Get the value of the index-th node in the linked list. If the index is invalid, return -1. 
+ * @param {number} index
+ * @return {number}
+ */
+MyLinkedList.prototype.getNode = function(index) {
+    if(index < 0 || index >= this._size) return null;
+    // 创建虚拟头节点
+    let cur = new LinkNode(0, this._head);
+    // 0 -> head
+    while(index-- >= 0) {
+        cur = cur.next;
+    }
+    return cur;
+};
+MyLinkedList.prototype.get = function(index) {
+    if(index < 0 || index >= this._size) return -1;
+    // 获取当前节点
+    return this.getNode(index).val;
+};
+
+/**
+ * Add a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list. 
+ * @param {number} val
+ * @return {void}
+ */
+MyLinkedList.prototype.addAtHead = function(val) {
+    const node = new LinkNode(val, this._head);
+    this._head = node;
+    this._size++;
+    if(!this._tail) {
+        this._tail = node;
+    }
+};
+
+/**
+ * Append a node of value val to the last element of the linked list. 
+ * @param {number} val
+ * @return {void}
+ */
+MyLinkedList.prototype.addAtTail = function(val) {
+    const node = new LinkNode(val, null);
+    this._size++;
+    if(this._tail) {
+        this._tail.next = node;
+        this._tail = node;
+        return;
+    }
+    this._tail = node;
+    this._head = node;
+};
+
+/**
+ * Add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted. 
+ * @param {number} index 
+ * @param {number} val
+ * @return {void}
+ */
+MyLinkedList.prototype.addAtIndex = function(index, val) {
+    if(index > this._size) return;
+    if(index <= 0) {
+        this.addAtHead(val);
+        return;
+    }
+    if(index === this._size) {
+        this.addAtTail(val);
+        return;
+    }
+    // 获取目标节点的上一个的节点
+    const node = this.getNode(index - 1);
+    node.next = new LinkNode(val, node.next);
+    this._size++;
+};
+
+/**
+ * Delete the index-th node in the linked list, if the index is valid. 
+ * @param {number} index
+ * @return {void}
+ */
+MyLinkedList.prototype.deleteAtIndex = function(index) {
+    if(index < 0 || index >= this._size) return;
+    if(index === 0) {
+        this._head = this._head.next;
+        this._size--;
+        return;
+    }
+    // 获取目标节点的上一个的节点
+    const node = this.getNode(index - 1);    
+    node.next = node.next.next;
+    // 处理尾节点
+    if(index === this._size - 1) {
+        this._tail = node;
+    }
+    this._size--;
+};
+
+// MyLinkedList.prototype.out = function() {
+//     let cur = this._head;
+//     const res = [];
+//     while(cur) {
+//         res.push(cur.val);
+//         cur = cur.next;
+//     }
+// };
+/**
+ * Your MyLinkedList object will be instantiated and called as such:
+ * var obj = new MyLinkedList()
+ * var param_1 = obj.get(index)
+ * obj.addAtHead(val)
+ * obj.addAtTail(val)
+ * obj.addAtIndex(index,val)
+ * obj.deleteAtIndex(index)
+ */
+```
+
 
 
 

problems/面试题02.07.链表相交.md

@@ -155,6 +155,42 @@ Python：
 
 Go：
 
+javaScript: 
+
+```js
+/**
+ * @param {ListNode} headA
+ * @param {ListNode} headB
+ * @return {ListNode}
+ */
+var getListLen = function(head) {
+    let len = 0, cur = head;
+    while(cur) {
+       len++;
+       cur = cur.next;
+    }
+    return len;
+} 
+var getIntersectionNode = function(headA, headB) {
+    let curA = headA,curB = headB, 
+        lenA = getListLen(headA),
+        lenB = getListLen(headB);
+    if(lenA < lenB) {
+        [curA, curB] = [curB, curA];
+        [lenA, lenB] = [lenB, lenA];
+    }
+    let i = lenA - lenB;
+    while(i-- > 0) {
+        curA = curA.next
+    }
+    while(curA && curA !== curB) {
+        curA = curA.next;
+        curB = curB.next;
+    }
+    return curA;
+};
+```
+