message: Fix bug in WeightMinHeap
diff: @@ -1848,13 +1848,14 @@ struct WeightMinHeap
  int i = c[0];
  int j = c.back();
  c.pop_back();
  + // Mark as removed
  + loc[i] = -1;
  + if (c.empty()) { return i; }
  double val = w[j];
  int pos = 0;
  pos = percolate_down(pos, val);
  c[pos] = j;
  loc[j] = pos;
  - // Mark as removed
  - loc[i] = -1;
  return i;
  }
  