public override char Move()
{
// First check if threathened
int[][] grid = game.GetBoard();
int gridSize = game.GetGridSize();
int mark = GetMark();
int otherMark;
char defendChoice = ' ';
char winningChoice = ' ';
char choice = ' ';
if (mark == 1)
{
otherMark = 2;
}
else
{
otherMark = 1;
}
// Players play either '1' or '2'
int count;
// Check rows
for (int row = 0; row < gridSize; row++)
{
count = 0;
for (int col = 0; col < gridSize; col++)
{
if (grid[row][col] == otherMark)
{
count++;
}
}
if (count == gridSize - 1)
{
// Defense
for (int col = 0; col < gridSize; col++)
{
if (grid[row][col] == 0)
{
defendChoice = (char)(row * gridSize + col + 97);
}
}
}
}
// Check columns
for (int col = 0; col < gridSize; col++)
{
count = 0;
for (int row = 0; row < gridSize; row++)
{
if (grid[row][col] == otherMark)
{
count++;
}
}
if (count == gridSize - 1)
{
// Defense
for (int row = 0; row < gridSize; row++)
{
if (grid[row][col] == 0)
{
defendChoice = (char)(row * gridSize + col + 97);
}
}
}
}
// Check positive diagonal
count = 0;
for (int row = 0, col = 0; (row < gridSize && col < gridSize); row++, col++)
{
if (grid[row][col] == otherMark)
{
count++;
}
}
if (count == gridSize - 1)
{
// Defense
for (int row = 0, col = 0; (row < gridSize && col < gridSize); row++, col++)
{
if (grid[row][col] == 0)
{
defendChoice = (char)(row * gridSize + col + 97);
}
}
}
// Check negative diagonal
count = 0;
for (int row = 0, col = gridSize - 1; (row < gridSize && col >= 0); row++, col--)
{
if (grid[row][col] == otherMark)
{
count++;
}
}
if (count == gridSize - 1)
{
// Defense
for (int row = 0, col = gridSize - 1; (row < gridSize && col >= 0); row++, col--)
{
if (grid[row][col] == 0)
{
defendChoice = (char)(row * gridSize + col + 97);
}
}
}
// See if we have learnt anything in the past
ArrayList alPossibilities = (ArrayList)memory.getChildTries(game.GetMoves());
if (alPossibilities != null)
{
if (alPossibilities.Count > 0)
{
// For the time being, select the first possibility
Trie t = (Trie)alPossibilities[new Random().Next(alPossibilities.Count)];
if (t.getValue() != null)
{
winningChoice = t.getChar();
}
else
{
choice = t.getChar();
}
}
else
{
}
}
else
{
// Go for a random placement
while (true)
{
choice = (char)(new Random().Next(game.GetGridSize() * game.GetGridSize()) + 97);
if (game.IsEmpty(choice))
{
break;
}
}
}
if (winningChoice != ' ')
{
choice = winningChoice;
}
else if (defendChoice != ' ')
{
choice = defendChoice;
}
return(choice);
}