wave 2 finished

Checkout Diagram.drawio

@@ -0,0 +1 @@
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lib/practice_exercises.rb

@@ -1,13 +1,61 @@
-
-# Time Complexity: ?
-# Space Complexity: ?
+require "pry"
+# Time Complexity: O(n2) because it is a nested loop.  Each loop runs n number of times where n is the 
+# length of the input test_array. Since the loops are nested, the loop will run n X n number of times.
+# Space Complexity: O(1) because the amount of memory used does not change as the size of the input changes. 
+list = [1, 2, 2, 3, 3, 4]
 def remove_duplicates(list)
-  raise NotImplementedError, "Not implemented yet"
+
+  i = 1
+  c = 0
+
+  while list[c] != nil
+    while list[c] == list[i]
+      list.delete_at(list[i])
+      i += 1
+    end
+    c += 1
+  end 
+  return list
 end
 
-# Time Complexity: ?
-# Space Complexity: ?
+
+# Time Complexity: O(n^3)
+# Space Complexity: O(1) because the amount of memory used does not change as the size of the input changes. 
+
+
 def longest_prefix(strings)
-  raise NotImplementedError, "Not implemented yet"
+
+  shortest_word = "pneumonoultramicroscopicsilicovolcanoconiosis" 
+
+  strings.each do |string|
+    if string.length < shortest_word.length 
+      shortest_word = string
+    end 
+  end 
+
+  prefix_array = []
+  strings.each_with_index do |string, index|
+    i = 0
+    shortest_word.each_char do |letter|
+      if letter != string[i]
+        prefix_array << shortest_word.slice(0..(i - 1))
+      end 
+      i += 1
+    end
+  end 
+
+  shortest_prefix = "pneumonoultramicroscopicsilicovolcanoconiosis" 
+
+  prefix_array.each do |prefix| 
+    if prefix.length < shortest_prefix.length
+      shortest_prefix = prefix
+    end
+  end 
+
+  return shortest_prefix 
 end
 
+
+
+
+

test/test_helper.rb

@@ -2,6 +2,7 @@
 require 'minitest'
 require 'minitest/autorun'
 require 'minitest/reporters'
+require "minitest/skip_dsl"
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new