Single-chain issues

/ * 
Is determined whether there is a single chain ring

1 ) Violence: double loops through (^ n- 2 )
 2 ) double Pointer: Pointer fast fast = NULL, slow pointer = SLOW NULL
 int Judge (Link head) 
{ 
    IF (head == NULL) return  to false ; 
    Link FAST = head , 
         SLOW = head;
     the while (SLOW FAST = = NULL &&!! NULL) 
    { 
        SLOW = slow-> Next; 
        FAST = FaST - PAK> next-> Next;
         IF (== SLOW FAST) 
        { 
            return  to true ; 
        } 
    } 
    return false;
}

Calculating the length of the belt loop of single chain

int count(link head)
{
    if(NULL==head)
        return false;
    link fast = head,
         slow = head;
    while(slow!=NULL && fast!=NULL)
    {
        slow = slow->next;
        fast = fast->next->next;
        if(slow==fast)
        {
            flag = true;
            break;
        }
    }
    if(flag)
    {
        int ans = 1;
        slow = slow->next;
        while(slow!=fast)
        {
            ans++;
            slow = slow->next;
        }
        return ans ;
    }
    return false;
}

Single linked list lookup entry ring

设环长为n，非环形部分长度为m
link find(link head)
{
    int flag = false;
    if(NULL==head) return false;
    link fast = head,
         slow = head;
    while(slow!=NULL && fast!=NULL)
    {
        slow = slow->next;
        fast = fast->next->next;
        if(slow==fast)
        {
            flag=true;
            break;
        }
    }
    if(flag)
    {
        slow = head;
        while(slow!=fast)
        {
            slow = slow->next;
            fast = fast->next;
        }
        return slow;
    }
    return NULL;
}