Arrays.java

public class Arrays {

    // Given 2 int arrays, a and b, each length 3, return a new array length 2 containing their middle elements. (http://codingbat.com/prob/p146449)

    public int[] middleWay(int[] a, int[] b) {
	int[] c = {a[1], b[1]};
	return c;
    }

    // Given an array of ints, return a new array length 2 containing the first and last elements from the original array. The original array will be length 1 or more.  (http://codingbat.com/prob/p101230)

    public int[] makeEnds(int[] nums) {
	int[] c = {nums[0], nums[nums.length - 1]};
	return c;
    }

    // Given a number n, create and return a new int array of length n, containing the numbers 0, 1, 2, ... n-1. The given n may be 0, in which case just return a length 0 array. You do not need a separate if-statement for the length-0 case; the for-loop should naturally execute 0 times in that case, so it just works. The syntax to make a new int array is: new int[desired_length].  (http://codingbat.com/prob/p180920)

    public int[] fizzArray(int n) {
	int[] c = new int[n];
	for(n-=1; n>0; n--)
	    c[n] = n;
	return c;
    }

    // Given an array of ints, return true if every element is a 1 or a 4.  (http://codingbat.com/prob/p186672)

    public boolean only14(int[] nums) {
	for(int i=nums.length-1; i>=0; i--) {
	    if (nums[i] != 1 && nums[i] != 4)
		return false;
	}
	return true;
    }

}