Compilare: main.cpp: In function 'std::vector<long long int> comb(std::vector<long long int>&, std::vector<long long int>&)': main.cpp:13:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); i++) { ~~^~~~~~~~~~ main.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < b.size(); j++) { ~~^~~~~~~~~~ main.cpp: In function 'std::vector<long long int> dfs(int, int)': main.cpp:28:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < b.size(); i++) { ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:62:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(taskname".inp", "r", stdin); ^ main.cpp:63:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(taskname".out", "w", stdout); ^ main.cpp:67:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(taskname".in", "r", stdin); ^ main.cpp:68:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(taskname".out", "w", stdout); ^