title: What is the complexity of this algorithm and is there a possibility to improve it?
body: <p>This is the algorithm of this problem: Write a function that takes two arrays as input, each array contains a list of A-Z; your program should return True if the
  2nd array is a subset of 1st array, or False if not.</p>
  <pre><code># Python 3 program to find whether an array
  
  def isSubset(arr1, arr2):
      i = 0
      for i in range(len(arr2)):
          if(arr2[i] not in arr1):
              return False
      return True
       
  arr1 = [&quot;A&quot;, &quot;B&quot;, &quot;C&quot;, &quot;D&quot;, &quot;E&quot;, &quot;F&quot;]
  arr2 = [&quot;C&quot;, &quot;A&quot;, &quot;A&quot;]
  
  if(isSubset(arr1, arr2)):
      print(&quot;arr2[] is a subset of arr1[] &quot;)
  else:
      print(&quot;arr2[] is not a subset of arr1[]&quot;)
  </code></pre>