diff --git a/lib/practice_exercises.rb b/lib/practice_exercises.rb
index 291e4e6..93d624a 100644
--- a/lib/practice_exercises.rb
+++ b/lib/practice_exercises.rb
@@ -1,13 +1,45 @@
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: n
+# Space Complexity: 1
 def remove_duplicates(list)
-  raise NotImplementedError, "Not implemented yet"
+  current = 0
+  result = 0
+
+  until list.length - 1 < current 
+    if list[result] != list[current] 
+      result += 1
+      list[result] = list[current]
+    end
+    current += 1
+  end
+  return list[0..result]
 end
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: n, as my algorithm needs to iterate through all elements.
+# Space Complexity: n, as I'm creating an array to store the characters in each iteration. More elements, longer the new array.
 def longest_prefix(strings)
-  raise NotImplementedError, "Not implemented yet"
-end
+  same = true
+  index = 0
+
+  while same  
+    array_characters = strings.map do |string|
+      string[index]
+    end
+
+    current = 0
+    until array_characters.length - 1 < current
+      if array_characters[current] == array_characters[0]
+        current += 1
+      else
+        same = false
+      end
+    end
+    index += 1
+  end  
 
+  if same == true
+    return strings.first[0..index]
+  else
+    return strings.first[0...index] 
+  end
+end 
\ No newline at end of file