Compilare: user.cpp: In function ‘int getint()’: user.cpp:28:55: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if (++ptr>=maxb) fread(buf,maxb,1,stdin),ptr=0; ^ user.cpp:31:55: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if (++ptr>=maxb) fread(buf,maxb,1,stdin),ptr=0; ^ user.cpp: In function ‘int main()’: user.cpp:147:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dans.in","r",stdin); ^ user.cpp:148:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dans.out","w",stdout); ^ user.cpp: In function ‘void solve()’: user.cpp:87:9: warning: ‘dr’ may be used uninitialized in this function [-Wmaybe-uninitialized] V[dr].push_back(st); ^