题解 | 【模板】序列操作

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

int main() {
    int q;
    cin >> q;
    
    vector<int> sequence;
    
    while (q--) {
        int op;
        cin >> op;
        
        switch (op) {
            case 1: {
                int x;
                cin >> x;
                sequence.push_back(x);
                break;
            }
            case 2: {
                sequence.pop_back();
                break;
            }
            case 3: {
                int i;
                cin >> i;
                cout << sequence[i] << endl;
                break;
            }
            case 4: {
                int i, x;
                cin >> i >> x;
                sequence.insert(sequence.begin() + i + 1, x);
                break;
            }
            case 5: {
                sort(sequence.begin(), sequence.end());
                break;
            }
            case 6: {
                sort(sequence.begin(), sequence.end(), greater<int>());
                break;
            }
            case 7: {
                cout << sequence.size() << endl;
                break;
            }
            case 8: {
                if (sequence.empty()) {
                    cout << endl;
                } else {
                    for (int i = 0; i < sequence.size(); i++) {
                        cout << sequence[i];
                        if (i != sequence.size() - 1) {
                            cout << " ";
                        }
                    }
                    cout << endl;
                }
                break;
            }
        }
    }
    
    return 0;
}