Compilare: user.cpp: In function ‘int main()’: user.cpp:63:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) ^ user.cpp:65:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<sol[i].size();j++) printf("%d ",sol[i][j]); ^ user.cpp:51:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in","r",stdin); ^ user.cpp:52:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out","w",stdout); ^ user.cpp:53:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:56:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n1,&n2); ^