题解 | 【模板】序列操作

#include<bits/stdc++.h>
using namespace std;
vector<int> v;
int main() {
    int q, op;
    cin >> q;
    while (q--) {
        cin >> op;
        if (op == 1) {
            int x;
            cin >> x;
            v.push_back(x);
        } else if (op == 2) {
            v.pop_back();
        } else if (op == 3) {
            int x;
            cin >> x;
            cout << v[x] << endl;
        } else if (op == 4) {
            int pos, x;
            cin >> pos >> x;
            v.push_back(0);
            for (int i = v.size(); i > pos; i--) {
                v[i] = v[i - 1];
            }
            v[pos + 1] = x;
        } else if (op == 5) {
            sort(v.begin(), v.end());

        } else if (op == 6) {
            sort(v.begin(), v.end());
            reverse(v.begin(), v.end());
        } else if (op == 7) {
            cout << v.size() << endl;
        } else {
            for (int i = 0; i < v.size(); i++) {
                cout << v[i] << " ";
            }
            cout << endl;
        }
    }
    return 0;
}