Compilare: main.cpp: In function 'int main()': main.cpp:25:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<a.size();j++) ~^~~~~~~~~ main.cpp:17:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("logs.in", "r", stdin); ^ main.cpp:18:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("logs.out", "w", stdout); ^