From a94cb7c44929fe0b1056090605ad19833f1e15ef Mon Sep 17 00:00:00 2001
From: eaball35 <eaball35@gmail.com>
Date: Mon, 16 Sep 2019 07:27:00 -0700
Subject: [PATCH 1/2] finished longest_prefix

---
 lib/practice_exercises.rb | 49 ++++++++++++++++++++++++++++++++-------
 1 file changed, 41 insertions(+), 8 deletions(-)

diff --git a/lib/practice_exercises.rb b/lib/practice_exercises.rb
index 291e4e6..82da9f7 100644
--- a/lib/practice_exercises.rb
+++ b/lib/practice_exercises.rb
@@ -1,13 +1,46 @@
-
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n^2)
+# Space Complexity: O(1)
 def remove_duplicates(list)
-  raise NotImplementedError, "Not implemented yet"
+  list.each_with_index do |value, index|
+    if index > 0 
+      if value == list[index - 1] 
+        list.slice!(index) 
+      end
+    end
+  end
+  return list
 end
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(logn)
+# Space Complexity: O(n)
+
 def longest_prefix(strings)
-  raise NotImplementedError, "Not implemented yet"
-end
 
+  min_string = strings.min { |a,b| a.length <=> b.length}
+  hi = min_string.length - 1
+  low = 0
+  mid = (hi + low)/2
+  commons = []
+
+  strings.each do |string|
+    if min_string == string.slice(low..hi)
+      commons << string
+    end
+  end
+  return min_string if commons.length == strings.length
+
+  until hi <= low
+    commons = []
+    hi -= 1
+    prefix = min_string.slice(low..hi)
+    
+    strings.each do |string|
+      if prefix == string.slice(low..hi)
+        commons << string
+      end
+    end
+    return prefix if commons.length == strings.length
+  end
+  
+  return ""
+end
\ No newline at end of file

From 81aaae7ffc4b38d74a5c71f319a260316af6554b Mon Sep 17 00:00:00 2001
From: Emily Ball <eaball35@gmail.com>
Date: Mon, 16 Sep 2019 22:15:11 -0700
Subject: [PATCH 2/2] Update practice_exercises.rb

---
 lib/practice_exercises.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/practice_exercises.rb b/lib/practice_exercises.rb
index 82da9f7..81cf80d 100644
--- a/lib/practice_exercises.rb
+++ b/lib/practice_exercises.rb
@@ -11,7 +11,7 @@ def remove_duplicates(list)
   return list
 end
 
-# Time Complexity: O(logn)
+# Time Complexity: O(n)
 # Space Complexity: O(n)
 
 def longest_prefix(strings)
@@ -43,4 +43,4 @@ def longest_prefix(strings)
   end
   
   return ""
-end
\ No newline at end of file
+end