[Misc] Quick code polish of csc_sampling_graph.cc. (#5957)

Co-authored-by: Ubuntu <ubuntu@ip-172-31-28-63.ap-northeast-1.compute.internal>

graphbolt/src/csc_sampling_graph.cc

@@ -185,9 +185,10 @@ c10::intrusive_ptr<SampledSubgraph> CSCSamplingGraph::SampleNeighbors(
   torch::Tensor subgraph_indices =
       torch::index_select(indices_, 0, picked_eids);
   torch::optional<torch::Tensor> subgraph_type_per_edge = torch::nullopt;
-  if (type_per_edge_.has_value())
+  if (type_per_edge_.has_value()) {
     subgraph_type_per_edge =
         torch::index_select(type_per_edge_.value(), 0, picked_eids);
+  }
   torch::optional<torch::Tensor> subgraph_reverse_edge_ids = torch::nullopt;
   if (return_eids) subgraph_reverse_edge_ids = std::move(picked_eids);
   return c10::make_intrusive<SampledSubgraph>(
@@ -250,7 +251,7 @@ c10::intrusive_ptr<CSCSamplingGraph> CSCSamplingGraph::LoadFromSharedMemory(
  * fanout is >= the number of neighbors (and replacement is set to false).
  *  - When the value is a non-negative integer, it serves as a minimum
  * threshold for selecting neighbors.
- * @param replace Boolean indicating whether the sample is preformed with or
+ * @param replace Boolean indicating whether the sample is performed with or
  * without replacement. If True, a value can be selected multiple times.
  * Otherwise, each value can be selected only once.
  * @param options Tensor options specifying the desired data type of the result.
@@ -263,14 +264,12 @@ inline torch::Tensor UniformPick(
   torch::Tensor picked_neighbors;
   if ((fanout == -1) || (num_neighbors <= fanout && !replace)) {
     picked_neighbors = torch::arange(offset, offset + num_neighbors, options);
+  } else if (replace) {
+    picked_neighbors =
+        torch::randint(offset, offset + num_neighbors, {fanout}, options);
   } else {
-    if (replace) {
-      picked_neighbors =
-          torch::randint(offset, offset + num_neighbors, {fanout}, options);
-    } else {
-      picked_neighbors = torch::randperm(num_neighbors, options);
-      picked_neighbors = picked_neighbors.slice(0, 0, fanout) + offset;
-    }
+    picked_neighbors = torch::randperm(num_neighbors, options);
+    picked_neighbors = picked_neighbors.slice(0, 0, fanout) + offset;
   }
   return picked_neighbors;
 }
@@ -298,7 +297,7 @@ inline torch::Tensor UniformPick(
  * fanout is >= the number of neighbors (and replacement is set to false).
  *  - When the value is a non-negative integer, it serves as a minimum
  * threshold for selecting neighbors.
- * @param replace Boolean indicating whether the sample is preformed with or
+ * @param replace Boolean indicating whether the sample is performed with or
  * without replacement. If True, a value can be selected multiple times.
  * Otherwise, each value can be selected only once.
  * @param options Tensor options specifying the desired data type of the result.