Compilare: user.cpp: In function ‘int check(int, int, int)’: user.cpp:23:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<h1[sum2%MOD].size();i++) ^ user.cpp:29:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<h2[sum2%MOD].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:39:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.in","r",stdin); ^ user.cpp:40:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.out","w",stdout); ^ user.cpp:41:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d",&a1,&a2,&a3,&a4,&a5); ^