private static int FindLeft(int[] input, int target, int i, int j)
{
int mid = (j - i) / 2 + i;
// Can't check to the left.
if (mid == 0)
{
return(mid);
}
if (input[mid] == target && input[mid - 1] != target)
{
return(mid);
}
else if (input[mid] == target || input[mid] > target)
{
// Answer is in the left half.
return(BoundariesFinder.FindLeft(input, target, i, mid));
}
else
{
// Answer is in right half.
return(BoundariesFinder.FindLeft(input, target, mid + 1, j));
}
}
private static int FindRight(int[] input, int target, int i, int j)
{
int mid = (j - i) / 2 + i;
if (mid + 1 == j)
{
return(mid + 1);
}
if (input[mid] == target && input[mid + 1] != target)
{
return(mid + 1);
}
else if (input[mid] == target || input[mid] < target)
{
// Answer is in the right half.
return(BoundariesFinder.FindRight(input, target, mid + 1, j));
}
else
{
// Answer is in left half.
return(BoundariesFinder.FindRight(input, target, 1, mid));
}
}
public static Tuple <int, int> Find(int[] input, int target)
{
return(new Tuple <int, int>(
BoundariesFinder.FindLeft(input, target, 0, input.Length),
BoundariesFinder.FindRight(input, target, 0, input.Length)));
}