Compilare: main.cpp: In function 'void add(int, int, int)': main.cpp:52:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = x; i <= a[no].size()-1; i += zeros(i)) ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'void solve(int)': main.cpp:88:44: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized] else if(a[j][poz[x]]==1) ga << last << "\n"; ^~~~