Function add

data_preprocessing/sample_key_points.cpp:24–34

int n, m;

void add(int u, int v) {
  Edge e;
  e.u = u; e.v = v;
  float dx = surface.V(u, 0) - surface.V(v, 0);
  float dy = surface.V(u, 1) - surface.V(v, 1);
  float dz = surface.V(u, 2) - surface.V(v, 2);
  e.l = sqrt(dx * dx + dy * dy + dz * dz);
  e.n = head[u];
  head[u] = edges.size();
  edges.push_back(e);
}

void spfa(int st) {
  std::queue<int> Q;