888 - Donkey

[Christian Schuster]

Hello folks. This problem seemd quite simple to me: Some backtracking+memoization (or DP) should be sufficient. However, I got a bunch of WAs within times comparable to the AC solutions. My solution uses the tuple of distances to the capital as memoization key. As I don't think my calculations are prone to floating point errors, there must be something else.

Are there any tricky cases? The only "special" case I could imagine is M=0, for which the result is 1.000 if player 1 starts, or 0.000 otherwise.

Except the creators of the input file, only two people got it AC yet, which makes me doubt the correctness of the input file. Please resolve my doubts!

[little joey]

Except the creators of the input file, only two people got it AC yet, which makes me doubt the correctness of the input file. Please resolve my doubts!

The other two people are not the worlds worst problemsolvers, and not many people have tried this problem yet, which makes me doubt the correctness of your program.
If you want, you can PM me your code and I'll run it against the judges input to resolve both our doubts.

[little joey]

To all other people having problems getting accepted: be sure to use the proper rounding. 0.0625 (1/16) and 0.9375 (15/16) should be rounded up to 0.063 and 0.938 respectively!

[lpereira]

Please provide me some testcases.
I've tested all I can imagine and all I get is WA...

[brianfry713]

Input:

Code: Select all

7
3 2 1 2 1
6 3 1 2 3 2
6 3 4 1 3 2
42 1 15 1
22 2 10 12 2
13 3 8 2 9 2
8 4 7 4 1 6 3

AC output:

Code: Select all

Game 1:the probability that player 1 wins = 0.667
Game 2:the probability that player 1 wins = 0.093
Game 3:the probability that player 1 wins = 0.366
Game 4:the probability that player 1 wins = 1.000
Game 5:the probability that player 1 wins = 0.224
Game 6:the probability that player 1 wins = 0.212
Game 7:the probability that player 1 wins = 0.222

[metaphysis]

This problem should employ special judge.