Remove Duplicates from Sorted List

Easy

Python

def delete_duplicates(head):
    cur=head
    while cur and cur.next:
        if cur.val==cur.next.val: cur.next=cur.next.next
        else: cur=cur.next
    return head

Java

public ListNode deleteDuplicates(ListNode head){
    ListNode cur=head;
    while(cur!=null&&cur.next!=null){
        if(cur.val==cur.next.val) cur.next=cur.next.next;
        else cur=cur.next;
    } return head;
}

Key Insight

Nearly identical. Python truthiness vs Java null checks.

Python → Java Differences

while cur and cur.next vs !=null
Skip or advance identical
Nearly identical

Python

def delete_duplicates(head):
    cur=head
    while cur and cur.next:
        if cur.val==cur.next.val: cur.next=cur.next.next
        else: cur=cur.next
    return head

Java

public ListNode deleteDuplicates(ListNode head){
    ListNode cur=head;
    while(cur!=null&&cur.next!=null){
        if(cur.val==cur.next.val) cur.next=cur.next.next;
        else cur=cur.next;
    } return head;
}

Algorithm Steps

1. If equal skip
2. Else advance

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