NC14661 简单的数据结构

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
vector<int>arr;
const int maxn = 50010;

int main()
{
    int n, m;
    cin >> n >> m;
    while (m--) {
        int num;
        cin >> num;
        if (num == 1) {
            int num1;
            cin >> num1;
            arr.insert(arr.begin(), num1);
        }
        else if (num == 2) {
            arr.erase(arr.begin());
        }
        else if (num == 3) {
            int num1;
            cin >> num1;
            arr.push_back(num1);
        }
        else if (num == 4) {
            arr.pop_back();
        }
        else if (num == 5) {
            reverse(arr.begin(), arr.end());
        }
        else if (num == 6) {
            cout << arr.size() << endl;
            for (int i = 0; i < arr.size(); i++) {
                cout << arr[i];
                if (i != arr.size() - 1)cout << " ";
            }
            cout << endl;
        }
        else {
            sort(arr.begin(), arr.end());
        }
    }
}