Compilare: user.cpp: In function ‘int main()’: user.cpp:94:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < H[i].size(); j ++) ^ user.cpp:36:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piese3.in", "r", stdin); ^