Compilare: main.cpp: In function 'void constr(int)': main.cpp:26:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[nod].size(); ++i) constr(v[nod][i]); ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void dfs(int)': main.cpp:31:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[nod].size(); ++i) if (!u[v[nod][i]]) dfs(v[nod][i]); ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void dfst(int)': main.cpp:35:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < vt[nod].size(); ++i) if (!ut[vt[nod][i]]) dfst(vt[nod][i]); ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < a.size(); ++k) { ~~^~~~~~~~~~ main.cpp:58:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sol[i].size(); ++j) g << sol[i][j] << ' '; ~~^~~~~~~~~~~~~~~