#6 Daily Problems -RemoveKFromList

Hi friends, This is my 6th day of solving one problem per day. I have started to solve the linked list related problems. Actually it is very interesting and fun to solve this type of problems.

Problem:

Note: Try to solve this task in O(n) time using O(1) additional space, where n is the number of elements in the list, since this is what you'll be asked to do during an interview.

Given a singly linked list of integers l and an integer k, remove all elements from list l that have a value equal to k.

Example

• For l = [3, 1, 2, 3, 4, 5] and k = 3, the output should be
  removeKFromList(l, k) = [1, 2, 4, 5];
• For l = [1, 2, 3, 4, 5, 6, 7] and k = 10, the output should be
  removeKFromList(l, k) = [1, 2, 3, 4, 5, 6, 7].

Input/Output

• [execution time limit] 3 seconds (java)
• [input] linkedlist.integer l
• A singly linked list of integers.
• Guaranteed constraints:
  0 ≤ list size ≤ 105,
  -1000 ≤ element value ≤ 1000.
• [input] integer k
• An integer.
• Guaranteed constraints:
  -1000 ≤ k ≤ 1000.
• [output] linkedlist.integer
• Return l with all the values equal to k removed.

My solution:

// Singly-linked lists are already defined with this interface:
// class ListNode<T> {
//   ListNode(T x) {
//     value = x;
//   }
//   T value;
//   ListNode<T> next;
// }
//
public ListNode<Integer> removeKFromList(ListNode<Integer> l, int k) {
    ListNode temp = l;

    // if give linked list is empty then return
    if (l == null){
        return l;
    }

    // iterate until given starting value are matching
    while(l.value == k ){
        l = l.next;
        if (l == null)
            return l;  // return, after the matching values and removed the remains are null
    }

    // check the next values are matching if matched then remove the elements from the linked list
    while(temp.next != null){
        if (temp.next.value.equals(k)){
            temp.next = temp.next.next;
        }else{
            temp=temp.next;
        }
    }
    return l;
 }

Ok friends, please help me to improve this solution ad help me to learn somethings from you. Thanks. lets meet tomorrow.

Happy coding!

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