ACM中的一道题提示presentation error

Question

求各位大神帮帮萌新解决一下，谢谢，我真的是解决不了了，都煎熬了8个小时了。

#include<string>

using namespace std;

const int MaxSize = 20;


class LinkList
{
private:
    struct Node *first;
public:
    LinkList();
    LinkList(int a[], int n);
    void Insert(int n);
    int Locate(int n);
    int Get(int n);
    int Delete(int n);
    int Length();
    void View();
};
struct Node
{
    int data;
    Node *next;
};
LinkList::LinkList()
{
    first = new Node;
    first->next = NULL;
}
LinkList::LinkList(int a[], int len)
{
    struct Node *rear;
    first = new Node;
    first->next = NULL;
    rear = first;
    for (int i = 0; i < len; i++)
    {
        rear = new Node;
        rear->data = a[i];
        first->next = rear;
        rear->next = NULL;

    }
}
void LinkList::Insert(int n)
{
    for (int t = 0; t < n ; t++)
        {
            int i;
            int x;
            cin >> i >> x;
            Node * rear;
            Node * s;
            rear = first;
            for ( int j=0; rear!=NULL&&j < i-1; j++)
            {
                rear = rear->next;
            }
            if (rear==NULL)
            {
                throw("位置不正确");
            }
            else
            {
                s = new Node;
                s->data = x;
                s->next = rear->next;
                rear->next = s;
            }


        }
}
int LinkList::Get(int n)
{
    Node *p = first->next;
    int count = 1;
    while (p!=NULL && count<n)
    {
        p = p->next;
        count++;
    }
    if (p==NULL)
    {
        throw"位置不正确";
    }
    else
    {
        return p->data;
    }

}
int LinkList::Delete(int i)
{
    Node *p;
    Node *q;
    int x;
    p = first;
    int count = 0;
    while (p!=NULL&&count<i-1)
    {
        p = p->next;
        count++;
    }
    if (p->next==NULL)
    {
        throw"位置不正确";
    }
    else if (first->next==NULL)
    {
        throw"下溢";
    }
    else
    {
        q = p->next;
        x = q->data;
        p->next = q->next;
        delete q;
        return x;

    }
}
int LinkList::Length()
{
    Node *p;
    int count = 0;
    p = first->next;
    while (p!=NULL)
    {
        p = p->next;
        count++;
    }
    return count;
}
void LinkList::View()
{
    Node *p;
    p = first->next;
    while (p!=NULL)
    {
        cout << p->data << endl;
        p = p->next;
    }
}
int LinkList::Locate(int x)
{
    Node *p;
    p = first->next;
    int count = 1;
    while (p!=NULL)
    {
        if (p->data==x)
        {
            return count;
        }
        p = p->next;
        count++;
    }
    throw"None";
    return 0;

}

int main()
{
    LinkList A;
    for (int i = 0; i < 8; i++)
    {
        string x;
        cin >> x;
        if (x == "I" )
        {
            int t;
            cin >> t;
            A.Insert(t);
        }
        else if (x =="S")
        {
            int t;
            cin >> t;
            cout<<A.Locate(t)<<endl;
        }
        else if (x =="G")
        {
            int t;
            cin >> t;
            cout<<A.Get(t)<<endl;
        }
        else if (x == "D")
        {
            int t;
            cin >> t;
            cout << A.Get(t) << endl;
            A.Delete(t);
        }
        else if (x =="L")
        {
            cout << A.Length() << endl;
        }
        else if (x =="V")
        {
            A.View();
        }
        else if (x =="E")
        {
            return 0;
        }
    }
    return 0;

}

Answer 1

https://wenku.baidu.com/view/0fe36ecb1a37f111f0855b04.html