Eliminate stacks disconnected from red DVONN pieces

[dvonn] / dvonn-board.c

diff --git a/dvonn-board.c b/dvonn-board.c
index 4aaac54aadc19bcb65f3a5f360c967206e417e51..5b7c106c311909b30a47d96dc7ff3c6e7ecaf418 100644 (file)
--- a/dvonn-board.c
+++ b/dvonn-board.c
@@ -239,6 +239,49 @@ dvonn_board_place (dvonn_board_t *board,
     return TRUE;
 }
 
+static void
+fill_living(dvonn_board_t *board,
+           int living[DVONN_BOARD_X_SIZE][DVONN_BOARD_Y_SIZE],
+           int x, int y)
+{
+    if (dvonn_board_cell_occupied (board, x, y) && ! living[x][y])
+    {
+       living[x][y] = 1;
+
+       fill_living (board, living, x - 1, y);
+       fill_living (board, living, x + 1, y);
+       fill_living (board, living, x, y - 1);
+       fill_living (board, living, x, y + 1);
+       fill_living (board, living, x + 1, y - 1);
+       fill_living (board, living, x - 1, y + 1);
+    }
+}
+
+static void
+eliminate_disconnected_stacks (dvonn_board_t *board)
+{
+    int x, y;
+    int living[DVONN_BOARD_X_SIZE][DVONN_BOARD_Y_SIZE];
+
+    for (x = 0; x < DVONN_BOARD_X_SIZE; x++)
+       for (y = 0; y < DVONN_BOARD_Y_SIZE; y++)
+           living[x][y] = 0;
+
+    for (x = 0; x < DVONN_BOARD_X_SIZE; x++)
+       for (y = 0; y < DVONN_BOARD_Y_SIZE; y++)
+           if (board->cells[x][y].contains_red)
+               fill_living (board, living, x, y);
+
+    for (x = 0; x < DVONN_BOARD_X_SIZE; x++)
+       for (y = 0; y < DVONN_BOARD_Y_SIZE; y++)
+           if (dvonn_board_cell_occupied (board, x, y) &&
+               ! living[x][y])
+           {
+               board->cells[x][y].type = DVONN_CELL_EMPTY;
+               board->cells[x][y].height = 0;
+           }
+}
+
 int
 dvonn_board_move (dvonn_board_t *board,
                  int x1, int y1,
@@ -261,6 +304,8 @@ dvonn_board_move (dvonn_board_t *board,
     board->cells[x1][y1].height = 0;
     board->cells[x1][y1].contains_red = FALSE;
 
+    eliminate_disconnected_stacks (board);
+
     dvonn_board_next_player (board);
 
     return TRUE;