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Discussion of Problem 1334. Checkers

HINT for this problem: with EVERY detail you want.
Posted by 198808xc 15 Sep 2010 19:51
I have submitted for about 100 times with my (another) ID and finally get AC. Here I want to say something about the problem.

1. Is this problem easy?
Yes, very much. I think this problem could be regarded as 'PROBLEM FOR BEGINNERS'.
BTW, I think after reading my note, EVERYONE will be able to solve the problem.

2. What does the chessboard look like?
The chessboard is a common 8*8-board. The coordinates are marked with a~h(lowercase) and 1~8. 'a1' is a black cell.

3. How many players are there?
EXACTLY TWO.

4. Are all the checkers put on the black cell of the board?
Yes.

5. What does it mean by JUMPING OVER?
B could JUMPING OVER A, if A is at one of the four corners of B. (Use coordinates, (-1, -1), (-1, 1), (1, -1), (1, 1)). Do NOT think there are far-away jumpings, such as 'a1' jumps over 'c3'.

6. It says that, after jumping over, the checker mustn't fall over the board, is it right?
Yes!

7. It says that, after jumping over, the checker must be located at a FREE cell. What does FREE mean?
It means EMPTY cell, a cell without ANYTHING (and, within the board boundary).

8. What does it mean by "ONE OF THE OPPONENTS" gets the opportunity?
Let us call the two players Alice and Bob.
After Bob, for example, makes a move, if one of Alice's checker could fell one of Bob's checker, OR one of Bob's checker could fell one of Alice's checker, we think that "ONE OF THE OPPONENTS" have the opportunity.
WARNING: In BOTH cases above, it was Bob who will lose the game at once.

9. Are there mistakes in the test data?
No. There are no checkers put outside the board (such as a9 or g3), and no two checkers at the same place.

10. Could the output be '32'?
Yes. You can construct the case yourself.

11. Could the output be 'Draw'?
Yes. You can construct the case yourself.

12. Why did the author of this note use nearly 100 times to get AC?
Maybe something was wrong with him. Don't be like him :)


At last, we take a look at some cases:
(1)
b2
a1
(Some other 30 moves)
Answer should be 2: Although 'a1' could not be felled by 'b2' (Question 6), but 'b2' could be felled by 'a1', so the second player loses at once (Question 8).

(2)
a1
d4
b2
c3
(Some other 28 moves)
In this case, we could NOT judge the result with the first 4 moves (Questions 7 & 8).

(3)
a1
h8
a3
h6
a5
h4
a7
h2
b2
g7
b4
g5
b6
g3
b8
g1
c1
f8
c3
f6
c5
f4
c7
f2
d2
e7
d4
e5
d6
e3
d8
e1
It's a 'Draw' game (Questions 6, 7 & 8).

So, Good luck for EVERYONE.
Re: HINT for this problem: with EVERY detail you want.
Posted by hoan 23 Dec 2010 21:54
thanx!!!
Re: HINT for this problem: with EVERY detail you want.
Posted by MOPDOBOPOT (USU) 5 May 2011 21:17
Thankyou, good tests! :)
Re: HINT for this problem: with EVERY detail you want.
Posted by grisha[SIAL 2010] 16 Sep 2012 22:16


Edited by author 16.09.2012 22:37