题解 | 【模板】序列操作

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

int main() {
    vector<long long int> v;
    int operat;
    while (cin >> operat){
        if (operat==1){
            long long int x;
            cin >> x;
            v.push_back(x);
            continue;
        }
        if (operat==2){
            if (v.size()==0)continue;
            v.pop_back();
            continue;
        }
        if (operat==3){
            int i;
            cin >> i;
            cout << v[i]<< endl;
            continue;
        }
        if (operat==4){
            int i;
            long long int x;
            cin >> i >> x;
            v.insert(v.begin() + i + 1,x);
            continue;
        }
        if (operat==5){
            sort(v.begin(), v.end());
            continue;
        }
        if (operat==6){
            sort(v.begin(), v.end(), greater<int>());
            continue;
        }
        if (operat==7){
            cout << v.size()<< endl;
            continue;
        }
        if (operat==8){
            if (v.size()==0)continue;
            for (int i = 0; i < v.size(); i++) {
                if (i > 0) cout << " ";  // 元素之间加空格
                cout << v[i];
            }
            cout << endl;
            continue;
        }
    }
}
// 64 位输出请用 printf("%lld")