Insertion Sort List LeetCode Programming Solutions | LeetCode Problem Solutions in C++, Java, & Python [💯Correct]

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Hello Programmers/Coders, Today we are going to share solutions to the Programming problems of LeetCode Solutions in C++, Java, & Python. At Each Problem with Successful submission with all Test Cases Passed, you will get a score or marks and LeetCode Coins. And after solving maximum problems, you will be getting stars. This will highlight your profile to the recruiters.

In this post, you will find the solution for the Insertion Sort List in C++, Java & Python-LeetCode problem. We are providing the correct and tested solutions to coding problems present on LeetCode. If you are not able to solve any problem, then you can take help from our Blog/website.

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Link for the Problem – Insertion Sort List– LeetCode Problem

Insertion Sort List– LeetCode Problem

Problem:

Given the head of a singly linked list, sort the list using insertion sort, and return the sorted list’s head.

The steps of the insertion sort algorithm:

1. Insertion sort iterates, consuming one input element each repetition and growing a sorted output list.
2. At each iteration, insertion sort removes one element from the input data, finds the location it belongs within the sorted list and inserts it there.
3. It repeats until no input elements remain.

The following is a graphical example of the insertion sort algorithm. The partially sorted list (black) initially contains only the first element in the list. One element (red) is removed from the input data and inserted in-place into the sorted list with each iteration.

Example 1:

Input: head = [4,2,1,3]
Output: [1,2,3,4]

Example 2:

Input: head = [-1,5,3,4,0]
Output: [-1,0,3,4,5]

Constraints:

• The number of nodes in the list is in the range [1, 5000].
• -5000 <= Node.val <= 5000

Insertion Sort List– LeetCode Solutions

Insertion Sort List Solution in C++:

class Solution {
 public:
  ListNode* insertionSortList(ListNode* head) {
    ListNode dummy(0);
    ListNode* prev = &dummy;  // the last (largest) of the sorted list

    while (head) {                  // current inserting node
      ListNode* next = head->next;  // cache next inserting node
      if (prev->val >= head->val)   // `prev` >= current inserting node
        prev = &dummy;              // move `prev` to the front
      while (prev->next && prev->next->val < head->val)
        prev = prev->next;
      head->next = prev->next;
      prev->next = head;
      head = next;  // update current inserting node
    }

    return dummy.next;
  }
};

Insertion Sort List Solution in Java:

class Solution {
  public ListNode insertionSortList(ListNode head) {
    ListNode dummy = new ListNode(0);
    ListNode prev = dummy; // the last (largest) of the sorted list

    while (head != null) {       // current inserting node
      ListNode next = head.next; // cache next inserting node
      if (prev.val >= head.val)  // `prev` >= current inserting node
        prev = dummy;            // move `prev` to the front
      while (prev.next != null && prev.next.val < head.val)
        prev = prev.next;
      head.next = prev.next;
      prev.next = head;
      head = next; // update current inserting node
    }

    return dummy.next;
  }
}

Insertion Sort List Solution in Python:

class Solution:
  def insertionSortList(self, head: ListNode) -> ListNode:
    dummy = ListNode(0)
    curr = head

    while curr:
      prev = dummy
      while prev.next and prev.next.val < curr.val:
        prev = prev.next
      next = curr.next
      curr.next = prev.next
      prev.next = curr
      curr = next

    return dummy.next