07. Priority Queue

Step 1: Watch priority Queue basic explanation here.

Implementation Using Heap

VI Prerequisites: Comparable in PQ for generic PQ

My Implementation of PQ

Output of above implementation:-

Default Max PQ in Java

In Java 8+ you can create a max priority queue via one of these methods:

Method 1:

PriorityQueue<Integer> maxPQ = new PriorityQueue<>(Collections.reverseOrder());

Method 2:

PriorityQueue<Integer> maxPQ = new PriorityQueue<>((a,b) -> b - a); 

Method 3:

PriorityQueue<Integer> maxPQ = new PriorityQueue<>((a,b) -> b.compareTo(a));

NOTE: Implementation ()s of priority Queue is totally same as heap DS function which is covered in heap DS.

Priority Queue --------- Heap

1. add() = minInsert()
2. peek() = getMin()
3. remove() = extractMin()

Step 2: Problem Link.

Step 3: Solution Link.