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:139:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<D[i].size(); ++j) ^ user.cpp:143:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j != D[i].size()-1 && P[D[i][j]].x == P[D[i][j+1]].x && P[D[i][j]].y == P[D[i][j+1]].y) ^ user.cpp:153:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j!=D[i].size()-1) ^