bubblesort2.cpp: In function 'std::vector<int> count_scans(std::vector<int>, std::vector<int>, std::vector<int>)':
bubblesort2.cpp:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<X.size();i++)
~^~~~~~~~~
/tmp/ccBssk1T.o: In function `main':
grader.cpp:(.text.startup+0x125): undefined reference to `countScans(std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status