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https://github.com/onyx-and-iris/grokking-algorithms.git
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55 lines
1.3 KiB
Python
55 lines
1.3 KiB
Python
import logging
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from tabulate import tabulate
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logging.basicConfig(
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level=logging.DEBUG,
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format="%(asctime)s %(levelname)s\n\r%(message)s",
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datefmt="%H:%M:%S",
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)
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logger = logging.getLogger(__name__)
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def longest_common_subsequence(X, Y, len_x, len_y):
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# create table and zero fill it
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table = [[0 for _ in range(len_x + 1)] for _ in range(len_y + 1)]
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for i in range(1, len_y + 1):
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for j in range(1, len_x + 1):
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if X[j - 1] == Y[i - 1]:
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table[i][j] = table[i - 1][j - 1] + 1
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else:
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table[i][j] = max(table[i - 1][j], table[i][j - 1])
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format_and_print(X, Y, table)
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return table[-1][-1]
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def format_and_print(X, Y, table):
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# enumerate first row (headings) + label each row in column0
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for i, row in enumerate(table):
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if i == 0:
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continue
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row[0] = Y[i - 1]
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table[0] = [None, *X]
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# print tabularised 2D array
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logger.info(tabulate(table, tablefmt="pretty"))
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X = "fosh"
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Y = "fort"
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logger.info(f"words: {X} {Y}")
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longest_subsequence = longest_common_subsequence(X, Y, len(X), len(Y))
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print(f"Longest common subsequence: {longest_subsequence}")
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X = "fosh"
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Y = "fish"
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logger.info(f"words: {X} {Y}")
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longest_subsequence = longest_common_subsequence(X, Y, len(X), len(Y))
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print(f"Longest common subsequence: {longest_subsequence}")
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