Compilare: user.cpp: In function ‘double dijkstra(int, int)’: user.cpp:102:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:142:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<D[i].size(); ++j) ^ user.cpp:151:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; k<D[i].size() && P[D[i][k]].x == P[D[i][j]].x && P[D[i][k]].y == P[D[i][j]].y; ++k) ^ user.cpp:153:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (k != D[i].size()) ^