Leetcode Problem 4

AllALessThanB.cs

/*
 * A [--|--]
 * B            [--|--]
 */
[Test]
public void AllOfAIsLessThanB()
{
    var nums1 = new int[]{1,2,3,4};
    var nums2 = new int[]{10,11,12,13,14};
    var appended = new int[] {1, 2, 3, 4, 10, 11, 12, 13, 14};
    var val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);
}

AllMixedIn.cs

[Test]
public void AllMixedIn()
{
    var nums1 = new int[] {0, 2, 4, 6, 8};
    var nums2 = new int[] {1, 3, 5, 7, 9};
    var appended = new int[] {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    var val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);

    nums1 = new int[] {2, 4, 6, 8};
    nums2 = new int[] {1, 3, 5, 7};
    appended = new int[] {1, 2, 3, 4, 5, 6, 7, 8};
    val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);
}

AndBMedianEqual.cs

/*
 * A   [--|--]
 * B [----|---]
 */
[Test]
public void AandBMediansAreEqual()
{
    var nums1 = new int[]{1,1,2,3,4};
    var nums2 = new int[]{0,1,2,3,4};
    var appended = new int[] {0, 1, 1, 1, 2, 2, 3, 3, 4, 4};
    var val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);
}

median.cs

public static double MedianOfArray(int[] nums)
{
    if (nums.Length == 0)
        return 0;

    if (nums.Length == 1)
        return nums[0];

    if (nums.Length % 2 == 0)
    {
        return ((double) (nums[nums.Length / 2] + nums[(nums.Length / 2) - 1])) / 2;
    }

    return nums[nums.Length/2];
}

MedianALessThanMedianB.cs

/*
 * A [--|---]
 * B  [---|--]
 */
[Test]
public void AisInBbutLessThanBMedian()
{
    var nums1 = new int[]{-1,0,1,2,3,4};
    var nums2 = new int[]{0,1,2,3,4};
    var appended = new int[] {-1,0,0,1,1,2,2,3,3,4,4};
    var val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);
}

solution.cs

public double FindMedianSortedArrays(int[] nums1, int[] nums2)
{

    if (nums1.Length == 0 && nums2.Length == 0)
        return 0;

    if (nums1.Length == 0)
        return MedianOfArray(nums2);

    if (nums2.Length == 0)
        return MedianOfArray(nums1);

    var totalLength = nums1.Length + nums2.Length;
    var arrLength = totalLength / 2+1;

    var buf = new int[arrLength];
    var Ai = 0;
    var Bi = 0;
    for (int i = 0; i < arrLength; i++)
    {
        if (Ai == nums1.Length)
        {
            buf[i] = nums2[Bi++];
            continue;
        }

        if (Bi == nums2.Length)
        {
            buf[i] = nums1[Ai++];
            continue;
        }


        if (nums1[Ai] < nums2[Bi])
            buf[i] = nums1[Ai++];
        else
            buf[i] = nums2[Bi++];

    }

    if (totalLength % 2 == 0)
    {
        return (buf[arrLength - 1] + buf[arrLength - 2]) / 2d;
    }
    return buf[arrLength - 1];

}

WeirdOnes.cs

[Test]
public void WeirdOnesIThoughtWereNeat()
{
    var nums1 = new int[]{1,1,1,100,100,100};
    var nums2 = new int[]{50,50,50};
    var appended = new int[] {1,1,1,50,50,50,100,100,100};
    var val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);

    nums1 = new int[] {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
    nums2 = new int[] {1, 2, 3, 4, 5};
    appended = new int[] {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5};
    val = MedianOfTwoSortedArrays_Problem.MedianOfArray(appended);
    _sut.FindMedianSortedArrays(nums1, nums2).ShouldBe(val);

}