Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:32:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘void dfs_topo(int)’: user.cpp:49:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘void solve(int, int, int)’: user.cpp:59:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘int main()’: user.cpp:81:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] valid[x] = 1; ^ user.cpp:82:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] valid[y] = 1; ^