Compilare: main.cpp: In function 'void dfs(int)': main.cpp:22:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[k].size(); ++i) { ~~^~~~~~~~~~~~~ main.cpp:19:9: warning: unused variable 'spec' [-Wunused-variable] int spec = 0; ^~~~ main.cpp: In function 'int main()': main.cpp:54:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[i].size(); ++j) { ~~^~~~~~~~~~~~~ main.cpp:65:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[i].size(); ++j) { ~~^~~~~~~~~~~~~