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https://github.com/onyx-and-iris/grokking-algorithms.git
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46 lines
995 B
Python
46 lines
995 B
Python
import logging
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import random
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logging.basicConfig(level=logging.DEBUG)
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logger = logging.getLogger(__name__)
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def binary_search(arr, low, high, x):
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# x not found, low has overlapped high so we return None
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if high < low:
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return
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mid = (high + low) // 2
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# x found at middle of split, return its index
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if arr[mid] == x:
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return mid
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# x in left side of split
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elif arr[mid] > x:
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return binary_search(arr, low, mid - 1, x)
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# x in right side of split
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else:
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return binary_search(arr, mid + 1, high, x)
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LOWER = 1000
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UPPER = 1000000
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SAMPLE_SIZE = 1000
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numbers = random.sample(range(LOWER, UPPER), SAMPLE_SIZE)
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numbers.sort()
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seen = set()
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count = 0
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result = None
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while result is None:
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guess = random.randrange(LOWER, UPPER)
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if guess not in seen:
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count += 1
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seen.add(guess)
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result = binary_search(numbers, 0, len(numbers) - 1, guess)
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print(f"Found {guess} at index {result} after {count} attempts.")
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