问题

以下是您要翻译的代码部分：

我已经在C++中编写了以下代码，用于从已排序的链表中删除重复项。

```cpp
#include <iostream>
using namespace std;

class Node
{
public:
    int data;
    Node *next;
    
    Node(int data)
    {
        this->data = data;
        this->next = NULL;
    }
};


void push(Node* &head, Node* &tail, int data)
{
    if(head==NULL)
    {
        Node* newNode = new Node(data);
        head = newNode;
        tail = newNode;
        return;
    }
    
    else
    {
        Node* newNode = new Node(data);
        tail->next = newNode;
        tail = newNode;
    }
}

void print(Node* &head)
{
    Node *temp = head;
    while(temp!=NULL)
    {
        cout<<temp->data<<" ";
        temp = temp->next;
    }
}

void removeDuplicates(Node* &head)
{
    if(head==NULL)
    {
        cout<<"Empty LL!";
        return;
    }
    
    if(head->next == NULL) 
    {
        cout << "Single Node in LL" << endl;
        return ;
    }
    
    Node* curr = head;
    
    while(curr!=NULL)
    {
        if(curr->next!=NULL && (curr->data == curr->next->data))
        {
            Node* temp = curr->next;
            curr->next = curr->next->next;
            temp->next = NULL;
            delete temp;
            
        }
        
        else
        {
             curr = curr->next;
        }
    }
}


int main()
{
    Node* head = NULL;
    Node* tail = NULL;
    
    push(head, tail, 25);
    push(head, tail, 50);
    push(head, tail, 50);
    push(head, tail, 67);
    print(head);
    cout<<endl;
    removeDuplicates(head);
    print(head);
    return 0;
}

虽然这段代码运行良好，但我的疑问是，在'if'块中删除重复节点后，为什么我们没有更新curr的值，比如curr = curr->next，以便将其发送到while循环中。否则while如何知道curr的更新值是什么？

PS：我仍然是C++的初学者

<details>
<summary>英文:</summary>
I&#39;ve written the following code in C++ which removes duplicates from a sorted Linked List.

#include <iostream>
using namespace std;

class Node
{
public:
int data;
Node *next;

Node(int data)
{
this->data = data;
this->next = NULL;
}

};

void push(Node* &head, Node* &tail, int data)
{
if(head==NULL)
{
Node* newNode = new Node(data);
head = newNode;
tail = newNode;
return;
}

else
{
Node* newNode = new Node(data);
tail -> next = newNode;
tail = newNode;
}

}

void print(Node* &head)
{
Node *temp = head;
while(temp!=NULL)
{
cout<<temp->data<<" ";
temp = temp->next;
}
}

void removeDuplicates(Node* &head)
{
if(head==NULL)
{
cout<<"Empty LL!";
return;
}

if(head -> next == NULL) 
{
cout << "Single Node in LL" << endl;
return ;
}
Node* curr = head;
while(curr!=NULL)
{
if(curr->next!=NULL && (curr->data == curr->next->data))
{
Node* temp = curr->next;
curr->next = curr->next->next;
temp->next = NULL;
delete temp;
}
else
{
curr = curr->next;
}
}

}

int main()
{
Node* head = NULL;
Node* tail = NULL;

push(head, tail, 25);
push(head, tail, 50);
push(head, tail, 50);
push(head, tail, 67);
print(head);
cout<<endl;
removeDuplicates(head);
print(head);
return 0;

}

While the code functions well, my doubt is that in the 'if' block, after deleting the duplicate node, why aren't we updating the value of curr like curr = curr -> next to send it to the while loop again. How else would while know what the updated value of curr is?
PS: Still a beginner in C++ :)
</details>
# 答案1
**得分**: 5
如果你从列表中移除下一个节点，可能仍然会有更多的重复项。如果你推进 `curr`，你只会删除每隔一个重复元素。
以下是当前代码的情况（`^`表示 `curr`，`---`表示下一次迭代，任何非数字节点内容仅用于标记不同的节点）
```plaintext
1(a) -&gt; 1(b) -&gt; 1(c) -&gt; 2(d)
^
---
1(a) -&gt; 1(c) -&gt; 2(d)
^
---
1(a) -&gt; 2(d)
^
---
1(a) -&gt; 2(d)
^

你建议的更改将导致以下结果

1(a) -> 1(b) -> 1(c) -> 2(d)
^
---
1(a) -> 1(c) -> 2(d)
        ^
---
1(a) -> 1(c) -> 2(d)
                ^

1(a) -> 1(b) -> 1(c) -> 2(d)
^
---
1(a) -> 1(c) -> 2(d)
^
---
1(a) -> 2(d)
^
---
1(a) -> 2(d)
^

1(a) -> 1(b) -> 1(c) -> 2(d)
^
---
1(a) -> 1(c) -> 2(d)
^
---
1(a) -> 1(c) -> 2(d)
^

答案2

得分: 3

因为你希望curr不受移除操作的影响，这样你可以将其与移除节点后的下一个节点进行比较。列表中可能有多个重复项，你希望移除除第一个以外的所有重复项。