public void BIT_Tests()
{
List <int> list = new List <int> {
1, 7, 3, 0, 5, 8, 3, 2, 6, 2, 1, 1, 4, 5
};
BinaryIndexedTree bit = new BinaryIndexedTree(list);
Assert.IsNotNull(bit);
Assert.AreEqual(43, bit.SumTo(12));
Assert.AreEqual(27, bit.SumTo(6));
Assert.AreEqual(23, bit.SumRange(1, 5));
bit.Update(4, 2);
Assert.AreEqual(45, bit.SumTo(12));
Assert.AreEqual(29, bit.SumTo(6));
Assert.AreEqual(25, bit.SumRange(1, 5));
}