title: what would be the best case scenario of merging two sorted array?
body: <p>i know that merging two sorted array takes O(m+n) time where m and n are the length of two arrays.</p>
  
  <p>maximum number of comparison would be (m+n-1).</p>
  
  <p>But one of my school teacher said that only average and worst case takes O(m+n) time. best cases takes O(1) time.</p>
  
  <p>here i am not able to understand how best case takes O(1).
  please mention best case scenario and how it takes O(1) time while answering .</p>