public void CombinationsWork()
{
var combinations = new FastCombinations <int>(new int[] { 1, 2, 3, 4, 5 }, 2)
.Select(x => x.ToArray()).ToList();
var seen = new HashSet <int[]>();
Assert.AreEqual(10, combinations.Count);
foreach (var item in combinations)
{
Assert.AreEqual(2, item.Length);
Assert.IsTrue(seen.Add(item.ToArray()), $"{item} was already seen");
}
}
public override string Solve_1()
{
var window = new HashSet <long>(input.Take(25));
for (int i = 25; i < input.Length; i++)
{
var isSum = new FastCombinations <long>(window.ToList(), 2).Where(x => x.Sum() == input[i]).Any();
if (!isSum)
{
xmasNumber = input[i];
return(xmasNumber.ToString());
}
_ = window.Remove(input[i - 25]);
_ = window.Add(input[i]);
}
return("?");
}
public void CombinationsDoNotAllocate()
{
var combinations = new FastCombinations <int>(new int[] { 1, 2, 3, 4, 5 }, 2).ToList();
Assert.IsTrue(ReferenceEquals(combinations[0], combinations[1]));
}
