Kth Largest element in array - java

gistfile1.java

public class KthLargest {
	public static int findKLargest(int[] ar, int low, int high, int k) {

		int pivotIndex = partition(ar, low, high);

		if (pivotIndex == k) {
			return ar[pivotIndex];
		}

		else if (pivotIndex > k) {
			return findKLargest(ar, low, pivotIndex - 1, k);
		}

		else {
			return findKLargest(ar, pivotIndex + 1, high, k);
		}
	}

	private static int partition(int[] ar, int low, int high) {
		int pivot = ar[low]; // first element as pivot

		int i = low + 1;
		for (int j = low + 1; j <= high; j++) {
			if (ar[j] < pivot) {
				swap(ar, i, j);
				i++;
			}
		}

		swap(ar, low, i - 1);

		return i - 1;
	}

	private static void swap(int[] ar, int i, int j) {
		int temp = ar[i];
		ar[i] = ar[j];
		ar[j] = temp;
	}

	public static void main(String[] args) {
		int inputArray[] = { 5, 4, 3, 2, 1 };
		int k = 3; // K is from [1...n]
		if (k > inputArray.length)
			System.out.println("K can not be larger than size of the array");
		else {
			int kLargest = findKLargest(inputArray, 0, inputArray.length - 1, k - 1);
			System.out.println(kLargest);
		}
	}

}