CODEWITHSUNDEEP
javac++queuedeque
hongtaesuk
hongtaesuk

Reputation: 667

What is the Java equivalent of C++ deque?

in C++ all I had to do was 

#include <queue> -> including
queue<int> a; -> defining
a.push(1); ->using

but in java I found very difficult to use simple deque what should I do...? more specifically, How should I code to simply do the same steps as I did in C++; including, defining, using.

even more specifically, I want to make a deque so that I can add any integer in the deque at front or back. and print whole numbers in that deque by the size of the deque

Upvotes: 5

Views: 2824

Answers (3)

Ryan Stewart
Ryan Stewart

Reputation: 128849

Java has both Queue and Deque types, and a LinkedList, among others, can act as either one:

import java.util.*;
Deque<Integer> q = new LinkedList<Integer>();
q.push(1);

Upvotes: 9

dsmith
dsmith

Reputation: 304

The current answers suggest that Java's java.util.LinkedList is the Java translation of C++'s std::deque. While LinkedList does have an interface that is roughly equivalent to that of std::deque, it does not provide the complexity guarantees that std::deque does. In particular, std::deque guarantees O(1) lookup by index (random access), while LinkedList has O(n) lookup. In this sense (the sense in which an experienced C++ user views std::deque), Java's LinkedList is nothing at all like std::deque (though it is very much like std::list). This thread provides a better answer to the question "What is is the Java equivalent of C++ deque". To sum up, there is no equivalent in the standard Java library.

Upvotes: 10

Paul
Paul

Reputation: 20061

Look at java.util.LinkedList.

LinkedList<Integer> linkedList = new LinkedList<Integer>();
linkedList.add(5);
linkedList.addFirst(2); // add to front, equivalent to push()
linkedList.addLast(3); // add to end, equivalent to add()

Upvotes: -1

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