Deque

Double Ended Queue

90% of vector operation we can do here . Here we can do 2 to 3 more operation .

int n ;
cin >> n ;
deque dq(n) ;
for(int i = 0 ;i  <= n ; i++){
//int x ;
//cin >> x ;
//dq.push_back(x) ;
cin >> dq[i] ;
}

dq.push_front(8) ;
dq.push_front(2) ;


for(auto value : dq)
{
cout << value << " " ;
}
cout << '\n' ;
sort(dq.begin(),dq.end()) ;
dq.pop_front() ;
for(auto value: dq)
{
cout << value << " " ;
}
cout << '\n' ;
}
}

Almost like a vector . Right?

In vector we can not insert at front in 0(1) . We can not delete at front in 0(1) .

Also can access the front value .
Last Element :

push_back()
pop_back()
back()->Access ;

First Element:

push_front()
pop_front()
front()

Drawback:
Here extra memory is used . When the dataset is very very big it is not efficient .Because here double pointer is used .