Compilare: user.cpp: In function ‘int main()’: user.cpp:41:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<B[1].size();i++) ^ user.cpp:59:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<B[z].size();i++) ^ user.cpp:76:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();i++) ^ user.cpp:26:14: warning: unused variable ‘z’ [-Wunused-variable] int i,nr,z,x,y,c; ^