shoes.cpp: In function 'll S(std::vector<int>&)':
shoes.cpp:22:6: warning: unused variable 'n' [-Wunused-variable]
22 | int n = s.size(), i = 0;
| ^
shoes.cpp: In function 'int main()':
shoes.cpp:9:27: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
9 | #define fp(a,i,c) for(int (a) = (i); (a) < (c); (a)++)
| ^
shoes.cpp:41:2: note: in expansion of macro 'fp'
41 | fp(i,0,2*n)
| ^~
/tmp/cc5wDGnL.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/cctD0yMz.o:shoes.cpp:(.text.startup+0x0): first defined here
/tmp/cc5wDGnL.o: In function `main':
grader.cpp:(.text.startup+0x278): undefined reference to `count_swaps(std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status