RotationPointbinarysearch.java

 static int rotationPoint(char[] values) {

        int start = 0;
        int end = values.length - 1;
        char startCharacter = values[0];

        while (start <= end) {
            int mid = (start + end) >>> 1;

            if (isRotationPoint(values, mid)) {
                return mid;
            } else if (values[mid] > startCharacter) {
                start = mid + 1;
            } else if (values[mid] < startCharacter) {
                end = mid - 1;
            }


        }
        return -1;
    }

    static boolean isRotationPoint(char[] values, int mid) {
        return values[mid - 1] > values[mid] && values[mid + 1] > values[mid];
    }