From 85c6865ae5f5f918a8004f20af9086549b47ac96 Mon Sep 17 00:00:00 2001
From: Jocelyn Wang <wangjoc@gmail.com>
Date: Thu, 15 Oct 2020 13:08:05 -0700
Subject: [PATCH 1/2] grouped anagrams

---
 lib/exercises.rb | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/lib/exercises.rb b/lib/exercises.rb
index e1b3850..d45aa96 100644
--- a/lib/exercises.rb
+++ b/lib/exercises.rb
@@ -1,11 +1,45 @@
 
 # This method will return an array of arrays.
 # Each subarray will have strings which are anagrams of each other
-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n * m)
+# Space Complexity: O(n)
 
 def grouped_anagrams(strings)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  words = {} 
+  
+  while !strings.empty? 
+    i, word_to_compare = 0, strings[0] 
+    words[word_to_compare] = []
+
+    while i < strings.length 
+      if permutation(word_to_compare, strings[i])
+        words[word_to_compare].push(strings[i])
+        strings.delete_at(i) 
+        i -= 1
+      end
+      i += 1 
+    end
+  end
+
+  return words.values
+end
+
+def permutation(str1, str2)
+  return true if str1.empty? && str2.empty?
+  return false if str1.nil? || str2.nil?
+  return false if str1.empty? || str2.empty?
+
+  hash = {}
+
+  str1.each_char do |char|
+    hash[char] ? hash[char] += 1 : hash[char] = 1
+  end
+
+  str2.each_char do |char|
+    hash[char] ? hash[char] -= 1 : false
+  end
+
+  return hash.values.all? { |value| value == 0 }
 end
 
 # This method will return the k most common elements

From 28e49af5ed5ff4cd3719ced557edf961198ae528 Mon Sep 17 00:00:00 2001
From: Jocelyn Wang <wangjoc@gmail.com>
Date: Thu, 15 Oct 2020 13:25:33 -0700
Subject: [PATCH 2/2] top k frequent

---
 lib/exercises.rb | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/lib/exercises.rb b/lib/exercises.rb
index d45aa96..7da0b9c 100644
--- a/lib/exercises.rb
+++ b/lib/exercises.rb
@@ -47,7 +47,29 @@ def permutation(str1, str2)
 # Time Complexity: ?
 # Space Complexity: ?
 def top_k_frequent_elements(list, k)
-  raise NotImplementedError, "Method hasn't been implemented yet!"
+  return [] if list.empty? || k == 0
+  
+  hash, result = [], []
+
+  list.each do |num|
+    hash[num] ? hash[num] += 1 : hash[num] = 1
+  end
+
+  k.times do |time|
+    max_count, top_occurence = 0, nil
+
+    list.each do |num|
+      if hash[num] > max_count
+        max_count = hash[num]
+        top_occurence = num
+      end
+    end
+
+    result << top_occurence
+    list -= [top_occurence]
+  end
+
+  return result
 end