Compilare: user.cpp: In function ‘void sift(int)’: user.cpp:19:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ls<=N && cost[h[son]]>cost[h[ls]]) ^ user.cpp:22:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(rs<=N && cost[h[son]]>cost[h[rs]]) ^ user.cpp: In function ‘int main()’: user.cpp:37:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int i=1;i<n;++i){ ^ user.cpp:48:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int i=1;i<=n;++i){ ^ user.cpp:54:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int i=1;i<=n;++i){ ^ user.cpp:61:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int i=n-1;i>=k+1;--i){ ^ user.cpp:66:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int t=0;t<G[nod].size();++t){ ^ user.cpp:81:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(register int jj=0;jj<G[j].size();++jj) ^