Compilare: user.cpp: In function ‘void solve()’: user.cpp:87:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i=0;i<nr;i++) ^ user.cpp:89:42: 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:106:29: 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:26:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&C); ^ user.cpp:32:27: 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:114:35: 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:115:37: 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:117:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^