Compilare: main.cpp: In function 'void Union(int, int)': main.cpp:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[a].size(); ++j) ~~^~~~~~~~~~~~~ main.cpp:23:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v[b].size(); ++j) ~~^~~~~~~~~~~~~ main.cpp:31:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < z.size(); ++i) ~~^~~~~~~~~~ main.cpp:33:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i+1 < z.size() && z[i] == z[i+1]) ~~~~^~~~~~~~~~ main.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < z.size(); ++i) ~~^~~~~~~~~~ main.cpp:44:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i+1 < z.size() && z[i] == z[i+1]) ~~~~^~~~~~~~~~