给定链表的头结点 head 请将其按 升序 排列并返回 排序后的链表不用递归不用迭代java用冒泡或者选择进行排序

以下是使用冒泡排序进行链表排序的示例代码：

public ListNode sortList(ListNode head) {
    if (head == null || head.next == null) {
        return head;
    }
    
    ListNode dummy = new ListNode(0);
    dummy.next = head;
    ListNode cur = dummy;
    int length = 0;
    
    // 计算链表长度
    while (cur.next != null) {
        cur = cur.next;
        length++;
    }
    
    for (int i = 0; i < length - 1; i++) {
        cur = dummy.next;
        ListNode prev = dummy;
        
        for (int j = 0; j < length - i - 1; j++) {
            if (cur.val > cur.next.val) {
                ListNode next = cur.next;
                cur.next = next.next;
                next.next = cur;
                prev.next = next;
            }
            
            prev = cur;
            cur = cur.next;
        }
    }
    
    return dummy.next;
}

以下是使用选择排序进行链表排序的示例代码：

public ListNode sortList(ListNode head) {
    if (head == null || head.next == null) {
        return head;
    }
    
    ListNode dummy = new ListNode(0);
    dummy.next = head;
    ListNode cur = dummy;
    
    while (cur.next != null) {
        ListNode minPre = findMinNodePre(cur);
        if (minPre == null) {
            break;
        }
        
        ListNode min = minPre.next;
        minPre.next = min.next;
        min.next = cur.next;
        cur.next = min;
        cur = cur.next;
    }
    
    return dummy.next;
}

private ListNode findMinNodePre(ListNode head) {
    ListNode minPre = head;
    ListNode min = head.next;
    ListNode cur = head.next;
    ListNode prev = head;
    
    while (cur != null) {
        if (cur.val < min.val) {
            minPre = prev;
            min = cur;
        }
        
        prev = cur;
        cur = cur.next;
    }
    
    return minPre;
}

以上两个示例代码中，ListNode 是链表节点的定义，包含一个整数值 val 和一个指向下一个节点的指针 next。head 是链表的头结点。函数 sortList 对链表进行排序，返回排序后的链表头结点