Compilare: user.cpp: In function ‘int main()’: user.cpp:310:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol[n].length();i++) ^ user.cpp:8:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grazing.in","r",stdin); ^ user.cpp:9:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grazing.out","w",stdout); ^ user.cpp:309:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^