STL双端队列

#include<deque>
#include<iostream>
using namespace std;
int main()
{
    deque<int> d={1,2,3,4};
    //访问首尾元素
    cout<<d.front()<<" "<<d.back()<<endl;
    cout<<*d.begin()<<" "<<*(d.end()-1)<<endl;
    cout<<d[0]<<" "<<d[3]<<endl;
    //添加头部元素
    d.push_front(0);
    //添加尾部元素
    d.push_back(5);
    for(auto &x: d) cout<<x<<" ";
    cout<<endl;
    //删除头部元素
    d.pop_front();
    //删除尾部元素
    d.pop_back();
    for(auto &x: d) cout<<x<<" ";
    cout<<endl;
    //使用emplace_front和emplace_back更加节省时间
    d.emplace_front(0);
    d.emplace_back(5);
    for(auto &x: d) cout<<x<<" ";
    return 0;
}