题解 | 【模板】序列操作

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

bool cmp(int x,int y){ //自定义cmp，实现sort从大到小排序
    return x>y;
}

int main() {
    int i, x, t, n;
    vector<int> a;
    cin>>n;
    while (n--) { //while 处理多个 case
        cin>>t;
        switch (t) {
            case 1:
                cin>>x;
                a.push_back(x);
                break;
            case 2:
                a.pop_back();
                break;
            case 3:
                cin>>i;
                cout<<a[i]<<endl;
                break;
            case 4:
                cin>>i>>x;
                a.insert(a.begin()+i+1, x);
                break;
            case 5:
                sort(a.begin(), a.end());
                break;
            case 6:
                sort(a.begin(), a.end(), cmp);
                break;
            case 7:
                cout<<a.size()<<endl;
                break;
            case 8:
                for(int i=0;i<a.size();i++) 
                    cout<<a[i]<<" ";
                cout<<endl;
                break;
        }
    }
    return 0;
}