Compilare: user.cpp: In function ‘int common(int)’: user.cpp:17:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s[i].size()>=len) ~~~~~~~~~~~^~~~~ user.cpp: In function ‘int main()’: user.cpp:86:16: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[200042]’ [-Wformat=] scanf("%s",&str); ^ user.cpp:80:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("frequent.in","r",stdin); ^ user.cpp:81:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("frequent.out","w",stdout); ^ user.cpp:83:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i",&k); ^ user.cpp:86:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",&str); ^