5 queue 和 deque

双端数组，可以再头部进行插入删除操作

deque与vector区别：

    1. vector对于头部的插入删除效率低，数据量越大，效率越低
    2. deque相对而言，头部插入删除快
    3. vector访问元素时的速度会比deque快。与内部实现有关。

构造deque

deque<type> d;
for(int i = 0;i<=n;i++)
{
    d.emplace_back(i);
}
deque<type> d2(d1.begin(),d1.end());
deque<type> d3(10,1);
deque<int> d4(d3);

遍历 const修饰后循环需要修改为const_iterator i =

void func(const deque<int>&d)
{
    for (deque<int>::const_iterator i = d.begin();i != d.end();i++)
    {
        cout << *i << endl;
        // const修饰不可修改deque内元素
    }
}

front() back()第一个/最后一个元素的引用

插入和删除

push_back(elem); emplace_back(elem);
push_front(elem);
pop_back(elem);
pop_front(elem);

insert(pos,elem);
insert(pos,n,elem);
insert(pos,beg,end);
clear();
erase(beg,end);
erase(pos);

eg

#include <iostream>
#include<vector>
#include<deque>
#include<algorithm>
#include<string>
#include<ctime>
#include <numeric>
using namespace std;
class Person{
public:
    Person(string name,int score)
    {
        this->m_name = name;
        this->m_score = score;
    }
    string m_name;
    int m_score;
};
void createPerson(vector<Person>&v)
{
    string nameSeed = "ABCDE";
    for (int i = 0; i <= 4;i++)
    {
        string name = "player";
        name += nameSeed[i];
        int score = 0;
        Person p(name,score);
        v.emplace_back(p);
    }
}
void rate(vector<Person> &v)
{
    for (auto& p:v)
    {
        deque<int> d;
        for (int i = 0; i < 10;i++)
        {
            int score = rand()%41+60;
            d.emplace_back(score);
        }

        sort(d.begin(), d.end());

/*        cout << " rating for " << p.m_name << ": " << endl;
        for (auto& i:d)
        {
            cout << i << "  " << endl;
        }
        */
        d.pop_back();
        d.pop_front();

        p.m_score = accumulate(d.begin(), d.end(), 0) / d.size();

    }
}
int main()
{
    srand((unsigned int)time(NULL));
    vector<Person> v;
    createPerson(v);
    rate(v);
    for(auto& p:v)
    {
        cout << "name : " << p.m_name << " score : " << p.m_score << endl;
    }
    return 0;
}

name : playerA score : 81
name : playerB score : 76
name : playerC score : 72
name : playerD score : 88
name : playerE score : 81

queue

    std::deque<int> values{ 1,2,3 };
    std::queue<int> my_queue(values);//{1,2,3}