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 x)
 {
    ListNode* node = (ListNode*)malloc(sizeof(ListNode));
    if(node == NULL)
    {
        exit(1);
    }
    node->val = x;
    node->next = NULL;
    return node;
 }
 ListNode* createcic(int n)
 {
    //创建第一个节点
    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 ) 
{
    //1.创建带环链表
    ListNode* prev = createcic(n);
    //2.遍历链表，删除节点
    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;
}