Create Kth Largest Element

Author: akshayavb99

Course 2 - Data Structures in JAVA/Lecture 21 - Priority Queues II/Kth Largest Element

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+/*
+Given an array A of random integers and an integer k, find and return the kth largest element in the array.
+Note: Try to do this question in less than O(N * logN) time.
+
+Input Format :
+The first line of input contains an integer, that denotes the value of the size of the array. Let us denote it with the symbol N.
+The following line contains N space separated integers, that denote the value of the elements of the array.
+The following contains an integer, that denotes the value of k.
+
+Output Format :
+The first and only line of output contains the kth largest element
+
+Constraints :
+1 <= N, Ai, k <= 10^5
+Time Limit: 1 sec
+
+Sample Input 1 :
+6
+9 4 8 7 11 3
+2
+Sample Output 1 :
+9
+
+Sample Input 2 :
+8
+2 6 10 11 13 4 1 20
+4
+Sample Output 2 :
+10
+*/
+
+import java.util.*;
+public class Solution {
+
+	public static int kthLargest(int n, int[] input, int k) {
+		// Write your code here
+		PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
+        for(int i=0;i<k;i++)
+        {
+            pq.add(input[i]);
+        }
+        
+        for(int i=k;i<input.length;i++)
+        {
+            int minVal=pq.peek();
+            if(minVal<input[i])
+                minVal=input[i];
+            if(minVal!=pq.peek())
+            {
+                pq.poll();
+                pq.add(minVal);
+            }
+        }
+        
+        int minVal=Integer.MAX_VALUE;
+        while(!pq.isEmpty())
+        {
+            int check=pq.poll();
+            if(check<minVal)
+                minVal=check;
+        }
+        return minVal;
+	}
+}