25 lines
648 B
Python
25 lines
648 B
Python
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def binary_search(search_list, value):
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list_empty(search_list)
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list_sorted(search_list)
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low = 0
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high = len(search_list) - 1
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while low <= high:
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middle = (low + high) // 2
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if search_list[middle] > value:
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high = middle - 1
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elif search_list[middle] < value:
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low = middle + 1
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else:
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return middle
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return "Item not found."
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def list_sorted(search_list):
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if not sorted(search_list) == search_list:
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raise ValueError("This list must be sorted.")
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def list_empty(search_list):
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if not search_list:
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raise ValueError('This list has no items.')
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