题解 | #环形链表的约瑟夫问题#

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param n int整型 
 * @param m int整型 
 * @return int整型
 */


typedef struct ListNode ListNode;

ListNode* BuyNode(int n)
{
    ListNode* pf = (ListNode*)malloc(sizeof(ListNode));
    if(pf==NULL)
    {
        exit(-1);
    }
    pf->val = n;
    pf->next = NULL;
    return pf;
}

ListNode* LinkList(int n)
{
    ListNode* phead = BuyNode(1);
    ListNode* ptail = phead;
    for(int i = 2;i<=n;i++)
    {
        ptail->next = BuyNode(i);
        ptail = ptail->next;
    }
    ptail->next = phead;
    return ptail;
}


int ysf(int n, int m ) 
{
    ListNode* prev = LinkList(n);
    ListNode* pcur = prev->next;
    int count = 1;
    while(pcur->next!=pcur)
    {
        if(count==m)
        {
            prev->next = pcur->next;
            free(pcur);
            pcur = prev->next;
            count = 1;
        }
        else 
        {
            prev = pcur;
            pcur = pcur->next;
            count++;
        }
    }
    return pcur->val;
}