Nara

lib/linked_list.rb

@@ -1,4 +1,3 @@
-
 # Defines a node in the singly linked list
 class Node
   attr_reader :data # allow external entities to read value but not write
@@ -18,71 +17,122 @@ def initialize
 
     # method to add a new node with the specific data value in the linked list
     # insert the new node at the beginning of the linked list
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(1)
+    # Space Complexity: O(1)
     def add_first(value)
-      raise NotImplementedError
+      new_node = Node.new(value, @head)
+      @head = new_node
     end
 
     # method to find if the linked list contains a node with specified value
     # returns true if found, false otherwise
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def search(value)
-      raise NotImplementedError
+      current = @head
+      while current 
+        if current.data == value
+          return true
+        end
+        current = current.next
+      end
+      return false 
     end
 
     # method to return the max value in the linked list
     # returns the data value and not the node
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: o(n)
+    # Space Complexity: O(1)
     def find_max
-      raise NotImplementedError
+      if @head == nil
+        return 
+      end
+      current = @head 
+      max = current.data
+      while current 
+        if current.data > max
+          max = current.data
+        end
+        current = current.next
+      end
+      return max
     end
 
     # method to return the min value in the linked list
     # returns the data value and not the node
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def find_min
-      raise NotImplementedError
+      if @head == nil
+        return 
+      end
+      current = @head 
+      min = current.data
+      while current 
+        if current.data < min
+          min = current.data
+        end
+        current = current.next
+      end
+      return min
     end
 
 
     # method that returns the length of the singly linked list
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def length
-      raise NotImplementedError
+      current = @head
+      count = 0
+      while current 
+        count += 1
+        current = current.next
+      end
+      return count
     end
 
     # method that returns the value at a given index in the linked list
     # index count starts at 0
     # returns nil if there are fewer nodes in the linked list than the index value
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def get_at_index(index)
-      raise NotImplementedError
+      current = @head
+      count = 0
+      while current 
+        if count == index 
+          return current.data 
+        elsif count > index
+          return
+        end
+        count += 1
+        current = current.next
+      end
     end
-
     # method to print all the values in the linked list
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: o(n)
     def visit
-      raise NotImplementedError
+      current = @head 
+      linked_list_values = []
+      while current
+        linked_list_values.push(current.data)
+        current = current.next
+      end
+      return linked_list_values
     end
 
     # method to delete the first node found with specified value
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def delete(value)
       raise NotImplementedError
     end
 
     # method to reverse the singly linked list
     # note: the nodes should be moved and not just the values in the nodes
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def reverse
       raise NotImplementedError
     end
@@ -117,25 +167,43 @@ def has_cycle
     # Additional Exercises 
     # returns the value in the first node
     # returns nil if the list is empty
-    # Time Complexity:  
-    # Space Complexity
+    # Time Complexity: O(1)
+    # Space Complexity: O(1)
     def get_first
-      raise NotImplementedError
+      if @head == nil 
+        return
+      else 
+        return @head.data
+      end
     end
 
     # method that inserts a given value as a new last node in the linked list
     # Time Complexity:  
     # Space Complexity
     def add_last(value)
-      raise NotImplementedError
+      new_node = Node.new(value)
+      if @head == nil 
+        @head = new_node
+        return
+      else
+        current = @head 
+        while current.next != nil 
+          current = current.next
+        end
+        current.next = new_node
+      end
     end
 
     # method that returns the value of the last node in the linked list
     # returns nil if the linked list is empty
     # Time Complexity:  
     # Space Complexity
     def get_last
-      raise NotImplementedError
+      current = @head 
+      while current 
+        current = current.next
+      end
+      return current.data
     end
 
     # method to insert a new node with specific data value, assuming the linked