Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:12:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[x].size();i++) ^ user.cpp: In function ‘void dfst(int)’: user.cpp:20:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<vt[x].size();i++) ^ user.cpp: In function ‘void dfsortop(int)’: user.cpp:42:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V[x].size();i++) ^ user.cpp: In function ‘void dfsfreetree(int)’: user.cpp:50:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<VP[x].size();i++) ^ user.cpp: In function ‘void build_trees()’: user.cpp:59:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<lista[i].size();j++) ^ user.cpp:60:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<v[lista[i][j]].size();k++) ^ user.cpp:73:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<V[x].size();j++) ^ user.cpp:81:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<V[x].size();j++) ^