Compilare: user.cpp: In function ‘void solve()’: user.cpp:76:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i=0;i<nr;i++) ^ user.cpp:78:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<sol[ ind[i] ].size();j++) ^ user.cpp: In function ‘void clear_data()’: user.cpp:95:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<used.size();i++) ^ user.cpp: In function ‘void read()’: user.cpp:24:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&C); ^ user.cpp:30:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&c); ^ user.cpp: In function ‘int main()’: user.cpp:103:35: 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); ^ user.cpp:104:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piese3.out","w",stdout); ^ user.cpp:106:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^