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Update adaptive_merge_sort.py

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ANANT JAIN 2024-10-17 01:52:29 +05:30 committed by GitHub
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commit b82503ee4a
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1 changed files with 8 additions and 65 deletions
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sorts/adaptive_merge_sort.py
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@ -1,61 +1,3 @@
def adaptive_merge_sort(sequence: list) -> list:
"""
Sorts a list using the Adaptive Merge Sort algorithm.
>>> adaptive_merge_sort([4, 3, 1, 2])
Initial sequence: [4, 3, 1, 2]
Sorting: array[0:2] and array[2:4]
Sorting: array[0:1] and array[1:2]
Merging: array[0:1] and array[1:2]
After merge: [3, 4]
Sorting: array[2:3] and array[3:4]
Skipping merge as array[2] <= array[3]
Merging: array[0:2] and array[2:4]
After merge: [1, 2, 3, 4]
Sorted sequence: [1, 2, 3, 4]
[1, 2, 3, 4]
"""
if len(sequence) < 2:
return sequence
aux = sequence[:]
print(f"Initial sequence: {sequence}")
adaptive_merge_sort_helper(sequence, aux, 0, len(sequence) - 1)
print(f"Sorted sequence: {sequence}")
return sequence
def adaptive_merge_sort_helper(array: list, aux: list, low: int, high: int) -> None:
"""
Helper function for Adaptive Merge Sort algorithm.
>>> adaptive_merge_sort_helper([4, 3, 1, 2], [4, 3, 1, 2], 0, 3)
Sorting: array[0:2] and array[2:4]
Sorting: array[0:1] and array[1:2]
Merging: array[0:1] and array[1:2]
After merge: [3, 4]
Sorting: array[2:3] and array[3:4]
Skipping merge as array[2] <= array[3]
Merging: array[0:2] and array[2:4]
After merge: [1, 2, 3, 4]
"""
if high <= low:
return
mid = (low + high) // 2
print(f"Sorting: array[{low}:{mid + 1}] and array[{mid + 1}:{high + 1}]")
adaptive_merge_sort_helper(aux, array, low, mid)
adaptive_merge_sort_helper(aux, array, mid + 1, high)
if array[mid] <= array[mid + 1]:
print(f"Skipping merge as array[{mid}] <= array[{mid + 1}]")
array[low : high + 1] = aux[low : high + 1]
return
merge(array, aux, low, mid, high)
def merge(array: list, aux: list, low: int, mid: int, high: int) -> None:
"""
Merges two sorted subarrays of the main array.
@ -68,19 +10,20 @@ def merge(array: list, aux: list, low: int, mid: int, high: int) -> None:
i, j = low, mid + 1
for k in range(low, high + 1):
if i > mid or (j <= high and array[j] < array[i]):
if i > mid:
aux[k] = array[j]
j += 1
else:
elif j > high:
aux[k] = array[i]
i += 1
elif array[i] <= array[j]:
aux[k] = array[i]
i += 1
else:
aux[k] = array[j]
j += 1
for k in range(low, high + 1):
array[k] = aux[k]
print(f"After merge: {array[low:high + 1]}")
# Example usage
if __name__ == "__main__":
print(adaptive_merge_sort([4, 3, 1, 2]))