Python merge sort











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In Algorithms Fourth Edition by Robert Sedgewick and Kevin Wayne, the exercise 2.2.10 states that:




Implement a version of merge() that copies the second half of a to
aux in decreasing order and then does the merge back to a. This
change al- lows you to remove the code to test that each of the halves
has been exhausted from the inner loop.




This is my code in Python:



def merge(a, lo, mi, hi): 
aux_hi = deque(a[mi:hi])
for i in range(lo, hi)[::-1]:
if aux_hi:
last_a = i-len(aux_hi)
if last_a < lo:
a[i] = aux_hi.pop()
else:
a[i] = aux_hi.pop() if aux_hi[-1] > a[last_a] else a[last_a]
else:
break


Have I implemented it as required? Or can it be improved further?










share|improve this question




























    up vote
    0
    down vote

    favorite












    In Algorithms Fourth Edition by Robert Sedgewick and Kevin Wayne, the exercise 2.2.10 states that:




    Implement a version of merge() that copies the second half of a to
    aux in decreasing order and then does the merge back to a. This
    change al- lows you to remove the code to test that each of the halves
    has been exhausted from the inner loop.




    This is my code in Python:



    def merge(a, lo, mi, hi): 
    aux_hi = deque(a[mi:hi])
    for i in range(lo, hi)[::-1]:
    if aux_hi:
    last_a = i-len(aux_hi)
    if last_a < lo:
    a[i] = aux_hi.pop()
    else:
    a[i] = aux_hi.pop() if aux_hi[-1] > a[last_a] else a[last_a]
    else:
    break


    Have I implemented it as required? Or can it be improved further?










    share|improve this question


























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      In Algorithms Fourth Edition by Robert Sedgewick and Kevin Wayne, the exercise 2.2.10 states that:




      Implement a version of merge() that copies the second half of a to
      aux in decreasing order and then does the merge back to a. This
      change al- lows you to remove the code to test that each of the halves
      has been exhausted from the inner loop.




      This is my code in Python:



      def merge(a, lo, mi, hi): 
      aux_hi = deque(a[mi:hi])
      for i in range(lo, hi)[::-1]:
      if aux_hi:
      last_a = i-len(aux_hi)
      if last_a < lo:
      a[i] = aux_hi.pop()
      else:
      a[i] = aux_hi.pop() if aux_hi[-1] > a[last_a] else a[last_a]
      else:
      break


      Have I implemented it as required? Or can it be improved further?










      share|improve this question















      In Algorithms Fourth Edition by Robert Sedgewick and Kevin Wayne, the exercise 2.2.10 states that:




      Implement a version of merge() that copies the second half of a to
      aux in decreasing order and then does the merge back to a. This
      change al- lows you to remove the code to test that each of the halves
      has been exhausted from the inner loop.




      This is my code in Python:



      def merge(a, lo, mi, hi): 
      aux_hi = deque(a[mi:hi])
      for i in range(lo, hi)[::-1]:
      if aux_hi:
      last_a = i-len(aux_hi)
      if last_a < lo:
      a[i] = aux_hi.pop()
      else:
      a[i] = aux_hi.pop() if aux_hi[-1] > a[last_a] else a[last_a]
      else:
      break


      Have I implemented it as required? Or can it be improved further?







      python algorithm sorting mergesort






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      share|improve this question




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      edited 5 mins ago









      Jamal

      30.2k11115226




      30.2k11115226










      asked 6 hours ago









      lerner

      1265




      1265



























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