Compilare: main.cpp: In function 'int main()': main.cpp:14:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a.size();i++) ~^~~~~~~~~ main.cpp:19:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a[j]==a[i] && j<a.size()) ~^~~~~~~~~ main.cpp:25:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j<a.size()) ~^~~~~~~~~