/**  
 * 计算链表中环的长度  
 *  
 * @author: Max Solider  
 * @date: 2022/10/9 14:18  
 * @param headNode  
 * @return int  
 */
 int findLoopLength(NormalListNode headNode) {  
    if (headNode == null || headNode.getNext() == null) {  
        return 0;  
    }  
    NormalListNode slowPtr = headNode, fastPtr = headNode;  
    boolean loopExists = false;  
    while (fastPtr.getNext() != null && fastPtr.getNext().getNext() != null) {  
        fastPtr = fastPtr.getNext().getNext();  
        slowPtr = slowPtr.getNext();  
        if (slowPtr == fastPtr) {  
            System.out.println("There is a loop in the linked list.");  
            loopExists = true;  
            break;        }  
    }  
    if (!loopExists) {  
        System.out.println("There is no loop in the linked list.");  
        return 0;  
    }  
    int loopLength = 1;  
    slowPtr = slowPtr.getNext();  
    while (slowPtr != fastPtr) {  
        slowPtr = slowPtr.getNext();  
        loopLength++;  
    }  
    System.out.println("The loop in the linked list has " + loopLength + " nodes");  
    return loopLength;  
}