From 1a2d3c20a58c726ab958312eb5788e725436b459 Mon Sep 17 00:00:00 2001
From: C Gutierrez <gutierrez.clara.es@gmail.com>
Date: Sun, 15 Sep 2019 21:48:44 -0700
Subject: [PATCH 1/2] exercises pass test to remove duplicates and list
 characters that are shared in a collection of strings

---
 lib/practice_exercises.rb | 66 +++++++++++++++++++++++++++++++++++----
 1 file changed, 60 insertions(+), 6 deletions(-)

diff --git a/lib/practice_exercises.rb b/lib/practice_exercises.rb
index 291e4e6..3a57e4c 100644
--- a/lib/practice_exercises.rb
+++ b/lib/practice_exercises.rb
@@ -1,13 +1,67 @@
-
-# Time Complexity: ?
-# Space Complexity: ?
+require 'pry'
+# Time Complexity: O(n) - as array size grows, the evaluation grows at the same rate 
+# Space Complexity: O(1) - no new data structures are being made
 def remove_duplicates(list)
-  raise NotImplementedError, "Not implemented yet"
+  if list.length == 1
+    return list
+  end
+  
+  i = 0
+  
+  list.each do |number|
+    if number[i+1] == number[i]
+      list.delete_at(i)
+    else 
+      i += 1
+    end
+  end
+  
+  return list
+  
 end
 
 # Time Complexity: ?
 # Space Complexity: ?
+
+# strings being passed in is an array of strings
 def longest_prefix(strings)
-  raise NotImplementedError, "Not implemented yet"
+  
+  max_length = strings[0].length
+  
+  return_statement = nil
+  
+  strings.each do |string|
+    if string.length > 0 && string.length < max_length
+      max_length = string.length
+    elsif string.length == 0
+      return_statement = ""
+    end
+  end
+  
+  if return_statement != nil
+    return return_statement
+  end
+  
+  i = 0 # I am the word you're on
+  j = 0 # I am the character you're on
+  k = 0 # I am the last characer that matched
+  # binding.pry
+  until j == max_length || i + 1 == strings.length do
+    if strings[i][j] == strings[i + 1][j]
+      i += 1
+      j += 1
+      k = j
+    else 
+      k -= 1
+      break
+    end
+    
+  end
+  
+  if k < 0
+    return ""
+  else
+    return_statement = strings[0][0...k]
+    return return_statement
+  end
 end
-

From 96e39e55a879a4b02d98256e67e5c69249caa86a Mon Sep 17 00:00:00 2001
From: C Gutierrez <gutierrez.clara.es@gmail.com>
Date: Sun, 15 Sep 2019 21:50:43 -0700
Subject: [PATCH 2/2] Added time and space complexity to common prefix problem

---
 lib/practice_exercises.rb | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/practice_exercises.rb b/lib/practice_exercises.rb
index 3a57e4c..1f5c3a3 100644
--- a/lib/practice_exercises.rb
+++ b/lib/practice_exercises.rb
@@ -20,8 +20,8 @@ def remove_duplicates(list)
   
 end
 
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n) - Although there are several loops, they are both proportional to the array being tested
+# Space Complexity: O(1) - no new data structures are being made
 
 # strings being passed in is an array of strings
 def longest_prefix(strings)
@@ -45,6 +45,7 @@ def longest_prefix(strings)
   i = 0 # I am the word you're on
   j = 0 # I am the character you're on
   k = 0 # I am the last characer that matched
+  
   # binding.pry
   until j == max_length || i + 1 == strings.length do
     if strings[i][j] == strings[i + 1][j]