cyberland.cpp: In function 'double solve(long long int, long long int, long long int, long long int, std::vector<long long int>, std::vector<long long int>, std::vector<long long int>, std::vector<long long int>)':
cyberland.cpp:9:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
9 | for(int i = 0 ;i <x.size() ;i ++){
| ~~^~~~~~~~~
/usr/bin/ld: /tmp/cclpCNMr.o: in function `main':
grader.cpp:(.text.startup+0x696): undefined reference to `solve(int, int, int, int, std::vector<int, std::allocator<int> >, 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