make steep happy

lib/compsci/heap.rb

@@ -79,8 +79,7 @@ def sift_down(idx = 0)
       return self if idx >= @tree.size
       cidxs = @tree.class.children_idx(idx, @tree.child_slots)
       # promote the heapiest child
-      cidx = self.heapiest(cidxs)
-      if !self.heapish?(idx, cidx)
+      if (cidx = self.heapiest(cidxs)) and !self.heapish?(idx, cidx)
         @tree.swap(idx, cidx)
         self.sift_down(cidx)
       end
@@ -96,7 +95,7 @@ def heapish?(pidx, cidx)
     # return the heapiest idx in cidxs
     #
     def heapiest(cidxs)
-      idx = cidxs.first
+      idx = cidxs.first or return nil
       cidxs.each { |cidx|
         idx = cidx if cidx < @tree.size and heapish?(cidx, idx)
       }
@@ -108,7 +107,7 @@ def heapiest(cidxs)
     # * calls heapish? on idx's children and then heap? on them recursively
     #
     def heap?(idx: 0)
-      check_children = []
+      check_children = Array.new
       @tree.class.children_idx(idx, @tree.child_slots).each { |cidx|
         # cidx may not be valid
         if cidx < @tree.size

sig/heap.rbs

@@ -0,0 +1,23 @@
+module CompSci
+  class Heap
+    @tree: CompleteTree
+    @cmp_val: Integer
+
+    attr_reader tree: CompleteTree
+    attr_reader cmp_val: Integer
+
+    def initialize: (?cmp_val: Integer,
+                     ?minheap: bool,
+		     ?child_slots: Integer) -> void
+
+    def push: (untyped node) -> self
+    def pop: () -> untyped
+    def sift_up: (?Integer idx) -> self
+    def sift_down: (?Integer idx) -> self
+    def heapish?: (Integer pidx, Integer cidx) -> bool
+    def heapiest: (Array[Integer] cidxs) -> Integer?
+    def heap?: (?idx: ::Integer) -> bool
+    def size: () -> Integer
+    alias count size
+  end
+end