[FEAT] Auto include & extract definations for cpp and some other languages.

[BeiChenStanly]

Auto include & extract definations

For example, the problem "2.add-two-numbers", the default codes are

/*
 * @lc app=leetcode.cn id=2 lang=cpp
 *
 * [2] add-two-numbers
 */
// @lc code=start
/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        
    }
};
// @lc code=end

After including & extracting definations, we can get

/*
 * @lc app=leetcode.cn id=2 lang=cpp
 *
 * [2] add-two-numbers
 */
#include <bits/stdc++.h>
using namespace std;
struct ListNode {
    int val;
    ListNode *next;
    ListNode() : val(0), next(nullptr) {}
    ListNode(int x) : val(x), next(nullptr) {}
    ListNode(int x, ListNode *next) : val(x), next(next) {}
};
// @lc code=start
/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        
    }
};
// @lc code=end

And we can set auto included files in the settings page. In this example, it is "bits/stdc++.h".

Motivation

It can save some time for those problems.

Contribution

We can add settings and use regex to match the codes in the block comment.

[BeiChenStanly]

#999 is working for this.