import java.util.concurrent.RecursiveTask;

/**
 * 
 */

/**
 * @author sbfan
 *
 */
public class FindMax extends RecursiveTask<Integer> {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private int low = 0;
	private int high = 0;
	private int[] array = null;
	private final int SEQUENTIAL_CUTOFF = 500;
	public FindMax(int[] arr, int lo, int hi) {
		low = lo;
		high = hi;
		array = arr;
	}
	
	/* (non-Javadoc)
	 * @see java.util.concurrent.RecursiveTask#compute()
	 */
	@Override
	protected Integer compute() {
		Integer max = Integer.MIN_VALUE;
		if(high - low <= SEQUENTIAL_CUTOFF) {
			for(int i = low; i < high; i++) {
				if(array[i] > max) {
					max = array[i];
				}
			}
		} else {
			int mid = (low + high)/2;
			FindMax left = new FindMax(array, low, mid);
			FindMax right = new FindMax(array, mid, high);
			left.fork();
			int rightMax = right.compute();
			int leftMax = left.join();
			max = Math.max(leftMax, rightMax);
		}
		return max;
	}

}