Compilare: user.cpp: In function ‘int main()’: user.cpp:20:32: warning: operation on ‘nrc’ may be undefined [-Wsequence-point] c[++nrc][++c[nrc][0]]=x; ^ user.cpp:48:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();++i) ^ user.cpp:63:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();++i) ^ user.cpp:75:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();++i) ^