删除排序链表中的重复元素

[Sunny Fu]

[Li Xiangyue]

var deleteDuplicates = function(head) {
    let temp = head;
    while(temp && temp.next){
        if(temp.val === temp.next.val){
            let next = temp.next
            temp.next = next.next
        }
        else{
            temp = temp.next
        }
    }
    return head
};

[Li Xiangyue]

删除排序链表中的重复元素II

var deleteDuplicates = function (head) {
    let dummyHead = new ListNode(0, head); 
    let prev = dummyHead;
    let cur = head;
    while (cur && cur.next) {
        if (cur.val === cur.next.val) { //值相同时
            let val = cur.val;
            while (cur && cur.val === val) { //找到不同值为止
                cur = cur.next
            }
            prev.next = cur; //前指针直接指向重复值之后的节点
        }
        else {
            prev = cur; //注意顺序
            cur = cur.next;

        }
    }
    return dummyHead.next;
};

[Nasuke]

删除链表中重复元素II

var deleteDuplicates = function(head) {
    let ret = new ListNode(null, head), p = ret
    if(!head) return head
    let arr = []
    while(p.next) {
        if(p.val == p.next.val) {
            arr.push(p.val)
        }
         p = p.next
    }
    p = ret 
    while(p.next){
        if(arr.includes(p.next.val)){
            p.next = p.next.next
        }else {
            p = p.next
        }
    }
    return ret.next

};

[Pcjmy]

题目链接：https://leetcode.cn/problems/remove-duplicates-from-sorted-list/description
时间复杂度：O(n)

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var deleteDuplicates = function(head) {
    let last=head;
    let node=head;
    if(node)
    {
        node=node.next;
        while(node)
        {
            if(node.val!=last.val)
            {
                last.next=node;
                last=node;
            }
            node=node.next;
        }
        last.next=null;
    }
    return head;
};

[Bbbtt04]

/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var deleteDuplicates = function(head) {
    let p = head;
    while(p && p.next) {
        if (p.val === p.next.val) {
            let next = p.next.next;
            p.next = next;
        } else {
            p = p.next;
        }
    }
    return head;
};