public void ArgumentOutOfRangeTest(int h, int w)
{
var cum = new FenwickTree2D(1, 1);
Assert.Throws <ArgumentOutOfRangeException>(() => cum.Add(h, w, 1));
Assert.Throws <ArgumentOutOfRangeException>(() => cum.Sum(h, w));
Assert.Throws <ArgumentOutOfRangeException>(() => cum.Sum(h, w, 0, 0));
Assert.Throws <ArgumentOutOfRangeException>(() => cum.Sum(0, 0, h, w));
}
public void AddTest()
{
var cum = new FenwickTree2D(1, 1);
const int expected = 1;
cum.Add(0, 0, expected);
var actual = cum.Sum(0, 0);
Assert.That(actual, Is.Zero);
actual = cum.Sum(1, 1);
Assert.That(actual, Is.EqualTo(expected));
}
public void SumRangeTest()
{
var random = new Random(0);
const int height = 50;
const int width = 50;
var ft = new FenwickTree2D(height, width);
var data = new long[height, width];
for (var i = 0; i < height; i++)
{
for (var j = 0; j < width; j++)
{
var value = random.Next(0, 10);
ft.Add(i, j, value);
data[i, j] = value;
}
}
var sum = new long[height + 1, width + 1];
for (var i = 1; i <= height; i++)
{
for (var j = 1; j <= width; j++)
{
sum[i, j] = sum[i, j - 1] + sum[i - 1, j] - sum[i - 1, j - 1] + data[i - 1, j - 1];
}
}
for (var h1 = 0; h1 <= height; h1++)
{
for (var w1 = 0; w1 <= width; w1++)
{
for (var h2 = h1; h2 <= height; h2++)
{
for (var w2 = w1; w2 <= width; w2++)
{
var sum1 = ft.Sum(h1, w1, h2, w2);
var sum2 = sum[h1, w1] + sum[h2, w2] - sum[h2, w1] - sum[h1, w2];
Assert.That(sum1, Is.EqualTo(sum2));
}
}
}
}
}
public void SumTest()
{
const int height = 3;
const int width = 3;
var cum = new FenwickTree2D(height, width);
for (var i = 0; i < height; i++)
{
for (var j = 0; j < width; j++)
{
cum.Add(i, j, 1);
}
}
for (var i = 0; i <= height; i++)
{
for (var j = 0; j <= width; j++)
{
var expected = i * j;
var actual = cum.Sum(i, j);
Assert.That(actual, Is.EqualTo(expected));
}
}
}