PriorityQueue class

import java.util.*;

public class Example {

    // leetcode 215
    public int findKthLargest(int[] nums, int k) {
        PriorityQueue<Integer> pq = new PriorityQueue<>();

        for(int i=0; i<nums.length; i++){
            pq.add(nums[i]);

            if(pq.size()>k){
                pq.poll(); // worthless element
            }
        }

        return pq.peek();
    }

    public static int minCostRope(int[] ropes){
        PriorityQueue<Integer> pq = new PriorityQueue<>();

        for(int i=0; i<ropes.length; i++){
            pq.add(ropes[i]);
        }

        int cost = 0;

        while(pq.size()>1){
            int smallestRope = pq.poll();
            int secondSmallestRope = pq.poll();

            cost += (smallestRope + secondSmallestRope);
            
            int newRope = smallestRope + secondSmallestRope;
            pq.add(newRope);
        }

        return cost;
    }

    // leetcode 1024
    public int lastStoneWeight(int[] stones) { 
        PriorityQueue<Integer> mpq = new PriorityQueue<>(Collections.reverseOrder()); // max pq
        
        for(int i=0; i<stones.length; i++){
            mpq.add(stones[i]);
        }

        while(mpq.size()>1){
            int top = mpq.poll();
            int secondTop = mpq.poll();

            int finalStone = top - secondTop;

            if(finalStone != 0){
                mpq.add(finalStone);
            }
        }

        if(mpq.size()>0){
            return mpq.peek();
        }

        return 0;
    }
    public static void main(String[] args) {
        // PriorityQueue<Integer> pq = new PriorityQueue<>(); // min pq

        // pq.add(5);
        // pq.add(-11);
        // pq.add(3);

        // System.out.println("Minimum value is : " + pq.peek());

        // int ele = pq.poll();
        // System.out.println(ele);

        // System.out.println("Minimum value is : " + pq.peek());


        // PriorityQueue<Integer> mpq = new PriorityQueue<>(Collections.reverseOrder()); // max pq

        // mpq.add(5);
        // mpq.add(-11);
        // mpq.add(3);

        // System.out.println("Maximum value is : " + mpq.peek());

        // int ele = mpq.poll();
        // System.out.println(ele);

        // System.out.println("Maximum value is : " + mpq.peek());

        int[] ropes = {4,3,2,6};

        System.out.println(minCostRope(ropes));
    }
}