Method swapPairs

src/com/blankj/medium/_0024/Solution.java:22–33

(ListNode head)

//    }

    public ListNode swapPairs(ListNode head) {
        ListNode preHead = new ListNode(0), cur = preHead;
        preHead.next = head;
        while (cur.next != null && cur.next.next != null) {
            ListNode temp = cur.next.next;
            cur.next.next = temp.next;
            temp.next = cur.next;
            cur.next = temp;
            cur = cur.next.next;
        }
        return preHead.next;
    }

    public static void main(String[] args) {
        Solution solution = new Solution();