快慢指針

#include<bits/stdc++.h>
using namespace std;
typedef int ElemType;
typedef int status;


typedef struct LNode{
    ElemType data;
    struct LNode *next;
} *LinkList;

int FindMidNode(LinkList L){
    LinkList slow,fast;
    slow = fast = L->next;
  
    while(fast->next != NULL){   //跳不出去什麼原因 
        if(fast->next->next!=NULL){  //fast跳兩次，low跳一次 
            
            fast=fast->next->next;
            slow = slow->next;
            
        }
     

    }
  
         return slow->data;
    
}

status CreateList_L(LinkList &L,int n){
    LinkList p,q;
    L= new LNode;
    L->next = NULL;
    q= L;
    cout<<"請輸入數據" ; 
    for(int  i = 1;i<=n;i++){
        p = new LNode;
        cin>>p->data;
        q->next = p;
        q = q->next;
        
    }
    q->next = NULL;
    return 1;
}

status Outptlist_L(LinkList L){
     LinkList  p;
     p=L->next;
     if(p==NULL){
         cout<<"該鏈表爲空"<<endl;
          
     }
     else {
         cout<<"該鏈表爲："<<endl; 
         while(p!=NULL){
             cout<<p->data<<" ";
             p=p->next;
         }
     }
     cout<<endl;
 }
int main (){
    LinkList L1;
    CreateList_L(L1,5);
  Outptlist_L(L1);
  cout<<"中間值:"<<endl;
    cout<<FindMidNode(L1);
    
    return 0;
}