代码随想录算法训练营第三天 | 链表理论基础 | 707.设计链表

要求太多，代码量太大，实在难以完成

在以前听说，好的程序员，可以在短时生成大量的代码，本题只方法才只有6个，根本不算多

每天手敲代码量太少，才是问题

#include <iostream>

class MyLinkedList {
private:
    struct Node {
        int val;
        Node* next;
        Node(int v): val(v), next(nullptr) {}
    };
    Node* visualHead;
    int len;
public:
    MyLinkedList() {
        visualHead = new Node {0};
        len = 0;
    }
    int get(int index) {
        if (len == 0 || index < 0 || index > len - 1) return -1;
        auto *p = visualHead->next;
        for ( ; index--; p = p->next);
        return p->val;
    }
    void addAtHead(int val) {
        Node *new_node = new Node {val};
        auto* old_next = visualHead->next;
        visualHead->next = new_node;
        new_node->next = old_next;
        ++len;
    }
    void addAtTail(int val) {
        Node *new_node = new Node {val};
        auto* p = visualHead;
        for (; p->next != nullptr; p = p->next);
        p->next = new_node;
        ++len;
    }
    void addAtIndex(int index, int val) {
        if (index < 0 || index > len) return;
        Node *new_node = new Node {val};
        auto *p = visualHead;
        for ( ; index--; p = p->next);
        new_node->next = p->next;
        p->next = new_node;
        ++len;
    }

    void deleteAtIndex(int index) {
        if (index >= len || index < 0) return;
        auto* p = visualHead;
        for (; index--; p = p->next);
        auto* delNode = p->next;
        p->next = p->next->next;
        delete delNode;
        delNode = nullptr;
        --len;
    }
};

int main()
{
    MyLinkedList mll {};
    mll.addAtHead(3);
    mll.addAtTail(5);
    mll.addAtIndex(2, 8);
    mll.addAtIndex(2, 7);
    std::cout << mll.get(1) << std::endl;
    std::cout << mll.get(0) << std::endl;
    std::cout << mll.get(2) << std::endl;
    std::cout << mll.get(3) << std::endl;
    return 0;
}

学习到的是在链中遍历时，使用index--是可以省略多定义变量的，但老师也说了，写成--index会死循环，是什么道理？

汇总