Compilare: main.cpp: In function 'void dfs(long long int, long long int)': main.cpp:86:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (ll i = 0; i < l1[el].size(); ++i) ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void union_find()': main.cpp:92:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (ll i = 0; i < x1.size(); ++i) { ~~^~~~~~~~~~~ main.cpp:102:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (ll i = 0; i < x2.size(); ++i) { ~~^~~~~~~~~~~