/// <summary>
/// Fills the leftInts array with all blocks as far up as possible
/// </summary>
/// <param name="column">column index</param>
/// <param name="leftInts">array to edit</param>
/// <param name="clueIndex">clue to use for this step in recursion</param>
/// <param name="colPos">current fill position of array. (used for recursion)</param>
/// <returns>false if a contradiction is encountered</returns>
private bool ColLeft(int column, int[] leftInts, int clueIndex, int colPos)
{
int clue = _ng.GetColumnNum(column, clueIndex);
if (clue == 0)
{
for (int i = colPos; i < _ng.Height; i++)
{
if (_ng.IsTrue(i, column))
{
return(false);
}
leftInts[i] = clueIndex * 2 - 1;
}
return(true);
}
int localPos = colPos;
bool posChanged;
while (true)
{
posChanged = false;
for (int i = localPos; i < localPos + clue; i++)
{
if (i >= leftInts.Length)
{
return(false);
}
if (_ng.IsFalse(i, column))
{
for (int j = localPos; j <= i; j++)
{
if (_ng.IsTrue(j, column))
{
return(false);
}
leftInts[j] = clueIndex * 2 - 1;
}
localPos = i + 1;
posChanged = true;
break;
}
leftInts[i] = clueIndex * 2;
}
if (posChanged)
{
continue;
}
if (localPos + clue >= leftInts.Length)
{
return(true);
}
if (!_ng.IsTrue(localPos + clue, column))
{
leftInts[localPos + clue] = clueIndex * 2 + 1;
if (ColLeft(column, leftInts, clueIndex + 1, localPos + clue + 1))
{
return(true);
}
if (_ng.IsTrue(localPos, column))
{
return(false);
}
}
leftInts[localPos] = clueIndex * 2 - 1;
localPos++;
}
}
