Compilare: main.cpp:1:2: warning: #import is a deprecated GCC extension [-Wdeprecated] #import<fstream> ^~~~~~ main.cpp:3:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main(){std::ifstream f("flip.in"); ^ main.cpp: In function 'int main()': main.cpp:4:30: warning: operation on 'E' may be undefined [-Wsequence-point] for(f>>O>>M;E<O*M;f>>U[E/M][E++%M]); ~^~ main.cpp:7:21: warning: operation on 'R' may be undefined [-Wsequence-point] for(S=R=0;R-O;S+=U[R++][E]*(I&1<<R?-1:1)); ~^~