ZOJ Problem Set - 1628
Diamond mine is a mini-game which is played on an 8 * 8 board as you can see below.
The board is filled with different colors of diamonds. The player can make one move at a time. A move is legal if it swaps two adjacent diamonds(not diagonally) and after that, there are three or more adjacent diamonds in a row or column with the same color. Those diamonds will be taken away and new diamonds will be put in their positions. The game continues until no legal moves exist.
The input contains several cases. Each case has exactly 9 lines. The first 8 lines each contains a string of 8 characters. The characters are 'R'(Red), 'O'(Orange), 'G'(Green), 'P'(Purple), 'W'(White), 'Y'(Yellow) or 'B'(Blue). All characters are uppercase. No 3 diamonds of the same color are initially in adjacent positions in a row or column. The last line has 4 integers in the form " row1 column1 row2 column2" describing the postions of the 2 diamonds that the player wants to swap. Rows are marked 1 to 8 increasingly from top to bottom while columns from left to right. Input is terminated by EOF.
For each case, output "Ok!" if the move is legal or "Illegal move!" if it is not.
Author: PAN, Minghao
Source: ZOJ Monthly, June 2003