题解 | 【模板】序列操作

#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

int main() {
    int q, n, x, i;
    vector<int> arr;
    cin >> q;
    while (q--) {
        cin >> n;
        switch (n) {
            case 1:
                cin >> x;
                arr.push_back(x);
                break;
            case 2:
                arr.pop_back();
                break;
            case 3:
                cin >> i;
                cout << arr[i] << endl;
                break;
            case 4:
                cin >> i >> x;
                arr.insert(arr.begin() + i + 1, x);
                break;
            case 5:
                sort(arr.begin(), arr.end());
                break;
            case 6:
                sort(arr.begin(), arr.end(), [](int a, int b) {  // lambda + sort 
                    return a > b;
                });
                break;
            case 7:
                cout << arr.size() << endl;
                break;
            case 8:
                for (auto& num : arr) {
                    cout << num << ' ';
                }
                cout << endl;
                break;


        }
    }
}
// 64 位输出请用 printf("%lld")