Create kthLargestElement.java

Author: Gourav-s12

Data Structure/Heap/kthLargestElement.java

@@ -0,0 +1,40 @@
+/*Find k’th largest element in an array
+Input:
+
+arr = [7, 4, 6, 3, 9, 1]
+k = 2
+
+Output:
+
+The 2nd largest array element is 7
+*/
+
+import java.util.*;
+class kthLargestElement
+{
+  public static void main (String args[])
+  {
+    int n,k;
+    // using max heap to solve and find kth largest element
+    Scanner s= new Scanner(System.in);
+    PriorityQueue < Integer > queue =
+      new PriorityQueue < Integer > (Comparator.reverseOrder ());
+    //using PriorityQueue as a heap data structure
+    System.out.println("enter the array length:");
+    n=s.nextInt();  //taking array length as a input
+    System.out.println("enter the element:");
+    for(int i=0;i<n;i++)
+        queue.add (s.nextInt()); //adding elements in heap (it does in-build sort)
+    System.out.println("enter the value of k:");
+    k=s.nextInt();  //taking the value of k 
+    if(k>n){
+        System.out.println("the value of k should not be more than array length!! error");
+        return;      // k must be less than n
+    }
+    while(k>1){
+        queue.poll (); //removing (k-1) elements from max heap
+        k--;           //so that next max element is the kth largest
+    }
+    System.out.println ("the kth largest element is:" + queue.peek ());//to get the max element in max heap (root element)
+  }
+}