Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:15:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < g[(sum - S) % mod].size(); i++) ^ user.cpp:22:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < g[sum % mod].size(); i++) ^ user.cpp:31:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < v[nod].size(); i++) ^ user.cpp:34:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < g[sum % mod].size(); i++) ^