Compilare: main.cpp: In function 'int main()': main.cpp:65:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < vec.size(); i++) { ~~^~~~~~~~~~~~ main.cpp:115:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ans.size(); i++) ~~^~~~~~~~~~~~ main.cpp:51:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("drum2.in", "r", stdin); ^ main.cpp:52:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("drum2.out", "w", stdout); ^ main.cpp:53:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:57:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &c[i]); ^