判断单链表是否有环？

最新推荐文章于 2023-04-06 17:44:24 发布

原创最新推荐文章于 2023-04-06 17:44:24 发布 · 333 阅读

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#null #list #struct #function #input

typedef struct LinkedList
{
    int data;
    LinkedList* pNext;
}LinkedList;

/**
* test 6, write a function to check whether there is loop in a linked list
* @param pList [input] linked list
* @return bool, if there is loop inside, return true, otherwise false
*/

bool isExistLoop(LinkedList* pList)
{
    if (pList == NULL || pList->pNext == NULL)
        return false;

    LinkedList* p1 = pList;
    LinkedList* p2 = pList;

    while (p2 != NULL && p2->pNext != NULL)
    {
        p1 = p1->pNext;
        p2 = p2->pNext->pNext;

        if (p1==p2)
            return true;
    }
    return false;
}