Merge remote-tracking branch 'refs/remotes/origin/ai' into ai

uttt.c

@@ -779,27 +779,80 @@ int main(int argc, char **argv) {
 
 int ut_boardValue(const char *tiles, int offset, int stride)
 {
-	int v = 0;
+	// could change this too..
+	int value = 0;
 	for(int r = 0; r < 3; r++)
 		for(int c = 0; c < 3; c++)
-			v += (T(r, c) == 'X') ? 1 : (T(r, c) == 'O') ? -1 : 0;
-	return v;
+			value += (T(r, c) == 'X') ? 1 : (T(r, c) == 'O') ? -1 : 0;
+	return value;
 }
-#define UT_VALUEMAX 81
-#define UT_VALUEMIN (-81)
+#define UT_VALUEMAX 81 * 2
+#define UT_VALUEMIN (-81 * 2)
 int ut_value(const struct ut_state *state)
 {
-	int v = 0;
+	int value = 0;
+
+	// game is won
 	char winner = ut_winner(state);
 	if(winner != '\0')
 	{
-		return (winner == 'X') ? 81 : (winner == 'O') ? -81 : 0;
+		return (winner == 'X') ? 81 * 2 : (winner == 'O') ? -81 * 2 : 0;
 	}
-	for(int r = 0; r < 3; r++)
-		for(int c = 0; c < 3; c++)
-			v += (state->boards[r][c] == '\0') ? ut_boardValue((char *)state->tiles, 27 * r + 3 * c, 9) :
-				            (state->boards[r][c] == 'X') ? 9 : (state->boards[r][c] == 'O') ? -9 : 0;
-	return v;
+
+	// weight each board: 2x if taken, 2x if blank but would lead to a 2-of-3
+	// line (for X or O), 1x otherwise
+	char importance[3][3] = {1};
+	for(int r = 0; r < 3; r++) {
+		for(int c = 0; c < 3; c++) {
+			char board = state->boards[r][c];
+			if (board == '\0') {
+				char b1, b2;
+				// horizontal
+				b1 = state->boards[r][(c+1)%3];
+				b2 = state->boards[r][(c+2)%3];
+				if (b2 < b1) { char tmp = b1; b1 = b2; b2 = tmp; }
+				if (b1 == '\0' && b2 != '\0') importance[r][c] = 2;
+				// vertical
+				b1 = state->boards[(r+1)%3][c];
+				b2 = state->boards[(r+2)%3][c];
+				if (b2 < b1) { char tmp = b1; b1 = b2; b2 = tmp; }
+				if (b1 == '\0' && b2 != '\0') importance[r][c] = 2;
+				// diagonals
+				if (r == c) {
+					b1 = state->boards[(r+1)%3][(c+1)%3];
+					b2 = state->boards[(r+2)%3][(c+2)%3];
+					if (b2 < b1) { char tmp = b1; b1 = b2; b2 = tmp; }
+					if (b1 == '\0' && b2 != '\0') importance[r][c] = 2;
+				}
+				if (r == 2 - c) {
+					b1 = state->boards[(r+1)%3][(c+2)%3];
+					b2 = state->boards[(r+2)%3][(c+1)%3];
+					if (b2 < b1) { char tmp = b1; b1 = b2; b2 = tmp; }
+					if (b1 == '\0' && b2 != '\0') importance[r][c] = 2;
+				}
+			}
+			else if (board == 'X') importance[r][c] = 2;
+			else if (board == 'O') importance[r][c] = 2;
+		}
+	}
+
+	// game is in progress
+	for(int r = 0; r < 3; r++) {
+		for(int c = 0; c < 3; c++) {
+			char board = state->boards[r][c];
+			int board_value;
+			if (board == '\0') {
+				// board is in progress
+				board_value = ut_boardValue((char *)state->tiles, 27 * r + 3 * c, 9);
+			} else {
+				// board is won
+				board_value = (board == 'X') ? 9 : (board == 'O') ? -9 : 0;
+			}
+			value += board_value * importance[r][c];
+		}
+	}
+
+	return value;
 }
 
 int ut_alphabetaq(const struct ut_state *state, struct ut_move move, int depth, int a, int b)