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60 lines
1.5 KiB
60 lines
1.5 KiB
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# coding: utf-8
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# In[1]:
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#Merge Slot Without Slicing
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#start is the index of the first item
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#end is the index past the the last item
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def indexMergeSort(alist, start = None, end = None):
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if start == None:
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start = 0
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if end == None:
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end = len(alist)
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#note that the print operations still use slicing for convenience
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#print("Input: ",alist[start:end])
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length = end - start
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if length > 1:
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#print("Splitting ",alist[start:end])
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mid = start + length//2
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indexMergeSort(alist, start, mid)
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indexMergeSort(alist, mid, end)
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i=start # index for the left part of the list
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j=mid # index for the right part of the list
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#we use a temporary list
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templist = [None] * (length)
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k = 0 #index for the temp list
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while i < mid and j < end:
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if alist[i] < alist[j]:
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templist[k] = alist[i]
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i=i+1
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else:
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#we swap
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templist[k] = alist[j]
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j=j+1
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k=k+1
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while i < mid:
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templist[k] = alist[i]
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i=i+1
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k=k+1
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while j < end:
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templist[k]=alist[j]
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j=j+1
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k=k+1
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#we copy the results
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for k in range(length):
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alist[start+k] = templist[k]
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#print("Merging ",alist[start:mid], alist[mid:end])
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alist = [54,26,93,17,77,31,44,55,20]
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indexMergeSort(alist)
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print(alist)
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