59 lines
1.4 KiB
Python
59 lines
1.4 KiB
Python
"""
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Author: Wenru Dong
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"""
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def levenshtein_dp(s: str, t: str) -> int:
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m, n = len(s), len(t)
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table = [[0] * (n) for _ in range(m)]
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for i in range(n):
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if s[0] == t[i]:
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table[0][i] = i - 0
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elif i != 0:
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table[0][i] = table[0][i - 1] + 1
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else:
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table[0][i] = 1
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for i in range(m):
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if s[i] == t[0]:
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table[i][0] = i - 0
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elif i != 0:
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table[i][0] = table[i - 1][0] + 1
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else:
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table[i][0] = 1
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for i in range(1, m):
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for j in range(1, n):
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table[i][j] = min(1 + table[i - 1][j], 1 + table[i][j - 1], int(s[i] != t[j]) + table[i - 1][j - 1])
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print(table)
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return table[-1][-1]
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def common_substring_dp(s: str, t: str) -> int:
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m, n = len(s), len(t)
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table = [[0] * (n + 1) for _ in range(m + 1)]
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for i in range(1, m + 1):
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for j in range(1, n + 1):
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table[i][j] = max(table[i - 1][j], table[i][j - 1], int(s[i - 1] == t[j - 1]) + table[i - 1][j - 1])
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return table[-1][-1]
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if __name__ == "__main__":
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s = "mitcmu"
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t = "mtacnu"
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print(levenshtein_dp(s, t))
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print(common_substring_dp(s, t))
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s = "kitten"
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t = "sitting"
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print(levenshtein_dp(s, t))
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print(common_substring_dp(s, t))
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s = "flaw"
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t = "lawn"
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print(levenshtein_dp(s, t))
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print(common_substring_dp(s, t)) |