BinarySearchAlgo.java

public class BinarySearchAlgo
{
	/** returns the largest index i such that array[i] ≤ needle */
	public static int largestMinor (int needle, int [] array)
	{
		int low = 0, high = array.length - 1;
		while (low < high) {
			int mid = (low + high + 1) / 2;
			if (needle < array[mid])
				high = mid - 1;
			else
				low = mid;
		}
		return low;
	}

	/** returns the smallest index i such that array[i] &ge; needle */
	public static int smallestMajor (int needle, int [] array)
	{
		int low = 0, high = array.length - 1;
		while (low < high) {
			int mid = (low + high) / 2;
			if (needle <= array[mid])
				high = mid;
			else
				low = mid + 1;
		}
		return low;
	}
}