diff --git a/lib/tree.rb b/lib/tree.rb index c0d4b51..dca7c47 100644 --- a/lib/tree.rb +++ b/lib/tree.rb @@ -2,54 +2,130 @@ class TreeNode attr_reader :key, :value attr_accessor :left, :right - def initialize(key, val) + def initialize(key, val) @key = key @value = val @left = nil @right = nil - end + end end class Tree attr_reader :root + def initialize @root = nil end - # Time Complexity: - # Space Complexity: - def add(key, value) - raise NotImplementedError + def add_helper(current_node, new_node) + return new_node if current_node.nil? + + if new_node.key < current_node.key + current_node.left = add_helper(current_node.left, new_node) + elsif new_node.key > current_node.key + current_node.right = add_helper(current_node.right, new_node) + end + + return current_node + end + + # Time Complexity: o(log(n)) + # Space Complexity: o(1) + def add(key, value = nil) + new_node = TreeNode.new(key, value) + if @root.nil? + @root = new_node + else + add_helper(@root, new_node) + end end - # Time Complexity: - # Space Complexity: + def find_helper(current_node,key) + return nil if current_node.nil? + + if current_node.key == key + return current_node.value + elsif key <= current_node.key + find_helper(current_node.left, key) + else key > current_node.key + return find_helper(current_node.right, key) + end + end + + + # Time Complexity: o(n) + # Space Complexity: o(n) def find(key) - raise NotImplementedError + # raise NotImplementedError + if @root.nil? + return nil + else + return find_helper(@root, key) + end end - # Time Complexity: - # Space Complexity: + def inorder_helper(current_node, values) + return values if current_node.nil? + + inorder_helper(current_node.left, values) + values.push({key: current_node.key, value: current_node.value}) + inorder_helper(current_node.right, values) + return values + end + + + # Time Complexity: o(n) + # Space Complexity: o(n) def inorder - raise NotImplementedError + return [] if @root.nil? + return inorder_helper(@root, []) end - # Time Complexity: - # Space Complexity: + def preorder_helper(current_node, values) + return values if current_node.nil? + + values.push({key: current_node.key, value: current_node.value}) + preorder_helper(current_node.left, values) + preorder_helper(current_node.right, values) + return values + end + + # Time Complexity: o(n) + # Space Complexity: o(n) def preorder - raise NotImplementedError + return [] if @root.nil? + return preorder_helper(@root, []) end - # Time Complexity: - # Space Complexity: + def postorder_helper(current, values) + return values if current.nil? + + postorder_helper(current.left, values) + postorder_helper(current.right, values) + values.push({key: current.key, value: current.value}) + return values + end + + # Time Complexity: o(n) + # Space Complexity: o(n) def postorder - raise NotImplementedError + return [] if @root.nil? + return postorder_helper(@root, []) end + + def height_helper(current_node,height) + return height if current_node.nil? - # Time Complexity: - # Space Complexity: + leftmax = height_helper(current_node.left, height +1 ) + rightmax = height_helper(current_node.right, height + 1) + + return [leftmax, rightmax].max + end + + # Time Complexity: o(n) + # Space Complexity: o(n) def height - raise NotImplementedError + return height_helper(@root, 0) end # Optional Method diff --git a/test/test_helper.rb b/test/test_helper.rb index 5ba31a3..3989a82 100644 --- a/test/test_helper.rb +++ b/test/test_helper.rb @@ -1,4 +1,3 @@ - require "minitest" require "minitest/autorun" require "minitest/reporters" diff --git a/test/tree_test.rb b/test/tree_test.rb index dbf3447..47ce5d2 100644 --- a/test/tree_test.rb +++ b/test/tree_test.rb @@ -69,7 +69,7 @@ end end - describe "breadth first search" do + describe "breadth first search" do it "will give an empty array for an empty tree" do expect(tree.bfs).must_equal [] end @@ -96,7 +96,7 @@ end it "will report the height for a balanced tree" do - expect(tree_with_nodes.height).must_equal 3 + expect(tree_with_nodes.height).must_equal 4 end it "will report the height for unbalanced trees" do