function maxSorted(x) {
    return x[x.length - 1];
}
The maximum is the highest number in the array. With a sorted array,
the last element in the array is always the largest, so this calculation
can be done in one step, or constant time.

@param {Array<number>} x input
@returns {number} maximum value
@example
maxSorted([-100, -10, 1, 2, 5]); // => 5