206-Reverse-Linked-List.cs

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     public int val;
 *     public ListNode next;
 *     public ListNode(int val=0, ListNode next=null) {
 *         this.val = val;
 *         this.next = next;
 *     }
 * }
 */
public class Solution
{
    public ListNode ReverseList(ListNode head)
    {
        ListNode prev = null, curr = head;

        while (curr != null)
        {
            var temp = curr.next;
            curr.next = prev;
            prev = curr;
            curr = temp;
        }
        return prev;
    }
}