Compilare: main.cpp: In function 'void Build()': main.cpp:18:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (g[j].size() == r) { ~~~~~~~~~~~~^~~~ main.cpp: In function 'int main()': main.cpp:51:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (dr[i] == 0 && st[i] == 0 && g[i].size() == r) { ~~~~~~~~~~~~^~~~