Compilare: user.cpp: In function ‘int main()’: user.cpp:121:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[val[i]].push_back(i); ^ user.cpp:125:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(int ii=0; ii< f[k].size(); ++ii) ^ user.cpp:125:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int ii=0; ii< f[k].size(); ++ii) ^ user.cpp:126:37: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(int jj=ii+1; jj< f[k].size(); ++jj){ ^ user.cpp:126:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int jj=ii+1; jj< f[k].size(); ++jj){ ^ user.cpp:104:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbpal.in","r",stdin); ^ user.cpp:105:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbpal.out","w",stdout); ^ user.cpp:107:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:111:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n",&x,&y); ^ user.cpp:120:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c ",&val[i]); ^