0432

Author: theforestvn88

0401-0500/0432_all_oone_data_structure.rb

@@ -0,0 +1,95 @@
+class AllOne
+    LLNode = Struct.new(:prev, :next, :val, :keys, :key) do
+        def append(key)
+            node = LLNode.new(nil, nil, val + 1, {})
+            node.prev = self
+            node.next = self.next
+            self.next&.prev = node
+            self.next = node
+            
+            node.keys[key] = true
+            node.key = key
+            node
+        end
+
+        def prepend(key)
+            node = LLNode.new(nil, nil, val - 1, {})
+            node.next = self
+            node.prev = self.prev
+            self.prev&.next = node
+            self.prev = node
+            
+            node.keys[key] = true
+            node.key = key
+            node
+        end
+
+        def delete_key(key)
+            self.keys.delete(key)
+            self.key = self.keys.keys.first if self.key = key
+        end
+
+        def remove
+            self.prev&.next = self.next
+            self.next&.prev = self.prev
+        end
+    end
+
+    def initialize()
+        @head = LLNode.new(nil, nil, 0, {}, nil)
+        @head.next = @head
+        @head.prev = @head
+        @key_to_node = Hash.new
+    end
+
+    def inc(key)
+        if @key_to_node.has_key?(key)
+            old_node = @key_to_node[key]
+            if old_node.next == @head || old_node.next.val > old_node.val + 1
+                @key_to_node[key] = old_node.append(key)
+            else
+                old_node.next.keys[key] = true
+                @key_to_node[key] = old_node.next
+            end
+            old_node.delete_key(key)
+            if old_node.keys.empty?
+                old_node.remove
+            end
+        else
+            if @head.next == @head || @head.next.val > 1
+                @key_to_node[key] = @head.append(key)
+            else
+                @head.next.keys[key] = true
+                @key_to_node[key] = @head.next
+            end
+        end
+    end
+
+    def dec(key)
+        if @key_to_node.has_key?(key)
+            old_node = @key_to_node[key]
+            if old_node.val == 1
+                @key_to_node.delete(key)
+            else
+                if old_node.prev == @head || old_node.prev.val < old_node.val - 1
+                    @key_to_node[key] = old_node.prepend(key)
+                else
+                    old_node.prev.keys[key] = true
+                    @key_to_node[key] = old_node.prev
+                end
+            end
+            old_node.delete_key(key)
+            if old_node.keys.empty?
+                old_node.remove
+            end
+        end
+    end
+
+    def get_max_key()
+       @head.prev.key || ""
+    end
+
+    def get_min_key()
+        @head.next.key || ""
+    end
+end