EPIJudge failed to run C++ test 'count_inversions.exe' with MSVC on windows

[spacelg]

Hi All,

Environment:
VS 2019 + Windows Server 2016

EPIJudge failed to run C++ test 'count_inversions.exe' with MSVC on windows. It can be reproduced on latest version b736406 on master branch. Could you please help look at this issue?

Repro steps:

1. git clone https://github.com/adnanaziz/EPIJudge F:\gitP\adnanaziz\EPIJudge
2. cd F:\gitP\adnanaziz\EPIJudge\epi_judge_cpp_solutions && mkdir build_amd64
3. cd build_amd64
4. cmake -G "Visual Studio 16 2019" -A x64 -DCMAKE_SYSTEM_VERSION=10.0.18362.0 -DCMAKE_BUILD_TYPE=Release ..
5. msbuild /m /p:Platform=x64 /p:Configuration=Release epi_judge_cpp_solutions.sln /t:Rebuild
6. cd F:\gitP\adnanaziz\EPIJudge\epi_judge_cpp_solutions\build_amd64\Release
7. .\count_inversions.exe

Error info:

[spacelg]

We can fix this test issue as below.

This function (in count_inversions.cc):
int CountSubarrayInversions(int start, int finish, vector* A_ptr) {

has several function calls in one expression. Compiler is allowed to call those fuctions in any order.
If you re-write the function like this:

int CountSubarrayInversions(int start, int finish, vector* A_ptr) {
if (finish - start <= 1) {
return 0;
}

int mid = start + ((finish - start) / 2);
int res = CountSubarrayInversions(start, mid, A_ptr);
res += CountSubarrayInversions(mid, finish, A_ptr);
res += MergeSortAndCountInversionsAcrossSubarrays(start, mid, finish, A_ptr);

return res;
}

Test passes with optimizations.