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Thomas MinhTu Hoang
in-place linked list reversal is more of an intellectual exercise than practical real-world code

Thomas MinhTu Hoang

Jul 13, 2025

// public class ListNode {
//     public int Val = 0;
//     public ListNode Next;

//     public ListNode(int value) {
//         this.Val = value;
//     }
// }

public class Solution {

    public ListNode reverse(ListNode head) {
      if (head?.Next == null) return head;

      ListNode fwd = head;
      ListNode bwd = null;

      while (fwd != null) {
        bwd = new ListNode(fwd.Val) { Next = bwd };
        fwd = fwd.Next;
      }

      return bwd;
    }

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Thomas MinhTu Hoang
Thomas MinhTu Hoang3 months ago

In practical real-world programming, mutating a shared data structure is usually a bad idea.

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