Compilare: main.cpp: In function 'void join(int, int, int)': main.cpp:45:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s[v].size() == val) ~~~~~~~~~~~~^~~~~~ main.cpp: In function 'int main()': main.cpp:71:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < vpos[val].size(); i++) ~~^~~~~~~~~~~~~~~~~~