从双向链表中删除所有出现的给定字符串

int StringList::remove(string value)
{
if ((head == NULL) || (value > tail->data) || (value < head->data))
{
    return false;
}

if ((head == tail) && (head->data == value))
{
    delete head;
    head = tail = NULL;
    return true;
}

if ((head->data) == value)
{
    head = head->next;
    delete head->previous;
    head->previous = NULL;
    return true;
}

if ((tail->data) == value)
{
    tail = tail->previous;
    delete tail->next;
    tail->next = NULL;
    return true;
}

Node *nodeToDelete = head;

while ((nodeToDelete->data) < value)
{
    nodeToDelete = nodeToDelete->next;
}

if ((nodeToDelete->data) == value)
{
    nodeToDelete->previous->next = nodeToDelete->next;
    nodeToDelete->next->previous = nodeToDelete->previous;
    delete nodeToDelete;
    return true;
}
else
{
    return false;
}
}

I have a doubly linked list here and im trying to remove all occurrences of a given string. Currently the function will only remove one occurrence, which is good but not quite working. I believe I need to somehow implement a counter variable that will count how many times the given string has been removed but im not quite sure how to go about it.

我在这里有一个双向链表,我试图删除所有出现的给定字符串。目前该功能只会删除一个事件,这很好但不太有效。我相信我需要以某种方式实现一个计数器变量,它将计算已删除给定字符串的次数,但我不太清楚如何去做。

full code: https://pastebin.com/3bRfJzJT

完整代码:https://pastebin.com/3bRfJzJT

2 个解决方案

#1

int StringList::remove(string value)
{
    Node* curr = head;
    while (curr != NULL)
    {
        if ((curr->data) == value)
        {
            if (curr == head)
            {
                head = curr->next;
                if (head->prev != NULL)
                    head->prev = NULL;
                else
                    tail = NULL;
                delete curr;
                curr = head;
            }
            else if (curr == tail)
            {
                tail = curr->prev;
                tail->next = NULL;
                delete curr;
                curr = NULL;
            }
            else
            {
                curr->prev->next = curr->next;
                curr->next->prev = curr->prev;
                Node* next = curr->next;
                delete curr;
                curr = next;
            }
        }
        else
            curr = curr->next;
    }
}

#2

int StringList::remove(string value)
{
    int numDeleted = 0;

    Node *node = head;
    while (node)
    {
        Node *nextNode = node->next;

        if (node->data == value)
        {
            if (head == node)
                head = head->next;

            if (tail == node)
                tail = tail->previous;

            if (node->previous)
                node->previous->next = node->next;

            if (node->next)
                node->next->previous = node->previous;

            delete node;
            ++numDeleted;
        }

        node = nextNode;
    }

    return numDeleted;
}

That being said, you really should use std::list instead of a manual list implementation. Let it handle the nodes for you, including removing values, eg:

话虽这么说,你真的应该使用std :: list而不是手动列表实现。让它为您处理节点,包括删除值,例如:

#include <list>

class StringList
{
private:
    std::list<std::string> data;

public:
    ...
    void remove(string value);
};

void StringList::remove(string value)
{
    data.remove(value);
}