Compilare: user.cpp: In function ‘int main()’: user.cpp:72:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0 ; i < sol.size() ; ++i) ^ user.cpp:26:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,a,b; ^ user.cpp:23:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.in","r",stdin); ^ user.cpp:24:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.out","w",stdout); ^ user.cpp:28:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:32:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^