Q24 (M): Swap Nodes in Pairs

class Solution {
    public ListNode swapPairs(ListNode head) {
        
        if(head == null || head.next == null)
            return head;
        
        ListNode curr = head;
        ListNode curr2 = head.next;
        while(curr2 != null){
            int tempVal = curr.val;
            curr.val = curr2.val;
            curr2.val = tempVal;
            curr = curr2.next;
            if(curr == null)
                break;
            curr2 = curr.next;
        }
        return head;
    
    }
}