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46 lines
1.1 KiB
Python
46 lines
1.1 KiB
Python
# Python program to implement Pigeonhole Sorting in python
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# Algorithm for the pigeonhole sorting
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def pigeonhole_sort(a):
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"""
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>>> a = [8, 3, 2, 7, 4, 6, 8]
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>>> b = sorted(a) # a nondestructive sort
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>>> pigeonhole_sort(a) # a destructive sort
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>>> a == b
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True
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"""
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# size of range of values in the list (ie, number of pigeonholes we need)
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min_val = min(a) # min() finds the minimum value
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max_val = max(a) # max() finds the maximum value
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size = max_val - min_val + 1 # size is difference of max and min values plus one
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# list of pigeonholes of size equal to the variable size
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holes = [0] * size
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# Populate the pigeonholes.
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for x in a:
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assert isinstance(x, int), "integers only please"
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holes[x - min_val] += 1
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# Putting the elements back into the array in an order.
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i = 0
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for count in range(size):
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while holes[count] > 0:
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holes[count] -= 1
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a[i] = count + min_val
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i += 1
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def main():
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a = [8, 3, 2, 7, 4, 6, 8]
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pigeonhole_sort(a)
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print("Sorted order is:", " ".join(a))
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if __name__ == "__main__":
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main()
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