Compilare: main.cpp: In function 'int solve(std::vector<std::pair<double, double> >)': main.cpp:12:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < V.size(); ++i) ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:20:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rays.in", "r", stdin); ^ main.cpp:21:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("rays.out", "w", stdout); ^ main.cpp:22:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:26:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] vx = (x > 0 ? x : -x); ^