The Problem: http://www.usaco.org/index.php?page=viewproblem2&cpid=1285↵
↵
The Editorial: http://www.usaco.org/current/data/sol_prob2_platinum_jan23.html↵
↵
I was stress testing against the model solution, and I think I found an error in the provided solution. ↵
↵
I ran this test case on the model solution as shown in the editorial:↵
↵
~~~~~↵
3 6↵
4 6 4 ↵
1 2 3↵
1 3 3↵
2 1 1↵
2 3 2↵
3 1 3↵
3 2 2↵
10↵
1 3↵
8 1↵
1 2↵
8 1↵
3 3↵
5 2↵
10 1↵
8 3↵
1 2↵
8 1↵
~~~~~↵
↵
It appears to be a valid test case adhering to the problem. However, when ran against the solution, I got a runtime error. The following was printed to standard error.↵
↵
~~~~~↵
Assertion failed: (a.f > b.f) && (a.s < b.s), file d:/C++ programs/usaco/jan/B/brute.cpp, line 36↵
~~~~~↵
↵
However, the correct answer to the test case is:↵
↵
↵
~~~~~↵
4↵
94↵
6↵
94↵
18↵
42↵
122↵
80↵
6↵
94↵
~~~~~↵
↵
↵
↵
Needless to say, I don't think this is correct. ↵
↵
Can the USACO staff please investigate this?↵
↵
↵
Edit: I have another test case which doesn't set off the assert, but sometimes gives either 7 (WA) or 12 (AC). (Perhaps it depends on the version of C++?), which means that the model solution also exhibits some strange undefined behavior.↵
↵
~~~~~↵
3 6↵
6 6 5 ↵
1 2 2↵
1 3 3↵
2 1 2↵
2 3 1↵
3 1 1↵
3 2 2↵
1↵
2 2↵
~~~~~↵
↵
Edit 2:↵
↵
I believe there may be a typo which caused that: On line 39, the model written:↵
↵
~~~~~↵
ll addOne = ((addOne%slopeDif)==0)?1:0;↵
~~~~~↵
↵
When it should be ↵
↵
~~~~~↵
ll addOne = ((addDif%slopeDif)==0)?1:0;↵
~~~~~↵
↵
The Editorial: http://www.usaco.org/current/data/sol_prob2_platinum_jan23.html↵
↵
I was stress testing against the model solution, and I think I found an error in the provided solution. ↵
↵
I ran this test case on the model solution as shown in the editorial:↵
↵
~~~~~↵
3 6↵
4 6 4 ↵
1 2 3↵
1 3 3↵
2 1 1↵
2 3 2↵
3 1 3↵
3 2 2↵
10↵
1 3↵
8 1↵
1 2↵
8 1↵
3 3↵
5 2↵
10 1↵
8 3↵
1 2↵
8 1↵
~~~~~↵
↵
It appears to be a valid test case adhering to the problem. However, when ran against the solution, I got a runtime error. The following was printed to standard error.↵
↵
~~~~~↵
Assertion failed: (a.f > b.f) && (a.s < b.s), file d:/C++ programs/usaco/jan/B/brute.cpp, line 36↵
~~~~~↵
↵
However, the correct answer to the test case is:↵
↵
↵
~~~~~↵
4↵
94↵
6↵
94↵
18↵
42↵
122↵
80↵
6↵
94↵
~~~~~↵
↵
↵
↵
Needless to say, I don't think this is correct. ↵
↵
Can the USACO staff please investigate this?↵
↵
↵
Edit: I have another test case which doesn't set off the assert, but sometimes gives either 7 (WA) or 12 (AC). (Perhaps it depends on the version of C++?), which means that the model solution also exhibits some strange undefined behavior.↵
↵
~~~~~↵
3 6↵
6 6 5 ↵
1 2 2↵
1 3 3↵
2 1 2↵
2 3 1↵
3 1 1↵
3 2 2↵
1↵
2 2↵
~~~~~↵
↵
Edit 2:↵
↵
I believe there may be a typo which caused that: On line 39, the model written:↵
↵
~~~~~↵
ll addOne = ((addOne%slopeDif)==0)?1:0;↵
~~~~~↵
↵
When it should be ↵
↵
~~~~~↵
ll addOne = ((addDif%slopeDif)==0)?1:0;↵
~~~~~↵
