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AmirMohammad Hosseini Nasab 2022-08-12 18:08:52 +04:30
parent 6e424f3c07
commit d224cfd1df
1 changed files with 7 additions and 5 deletions
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12
dynamic_programming/regex_match.py
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@ -12,8 +12,8 @@ def recursive_match(text: str, pattern: str) -> bool:
""" """
Recursive matching algorithm. Recursive matching algorithm.
Time complexity: O(2 ^ (m + n)), where m is the length of text and n is the length of pattern. Time complexity: O(2 ^ (|text| + |pattern|))
Space complexity: Recursion depth is O(m + n). Space complexity: Recursion depth is O(|text| + |pattern|).
:param text: Text to match. :param text: Text to match.
:param pattern: Pattern to match. :param pattern: Pattern to match.
@ -57,8 +57,8 @@ def dp_match(text: str, pattern: str) -> bool:
""" """
Dynamic programming matching algorithm. Dynamic programming matching algorithm.
Time complexity: O(m * n), where m is the length of text and n is the length of pattern. Time complexity: O(|text| * |pattern|)
Space complexity: O(m * n). Space complexity: O(|text| * |pattern|)
:param text: Text to match. :param text: Text to match.
:param pattern: Pattern to match. :param pattern: Pattern to match.
@ -91,7 +91,9 @@ def dp_match(text: str, pattern: str) -> bool:
if pattern[j - 1] == "." or pattern[j - 1] == text[i - 1]: if pattern[j - 1] == "." or pattern[j - 1] == text[i - 1]:
dp[i][j] = dp[i - 1][j - 1] dp[i][j] = dp[i - 1][j - 1]
elif pattern[j - 1] == "*": elif pattern[j - 1] == "*":
dp[i][j] = dp[i][j - 2] or ((pattern[j - 2] == "." or pattern[j - 2] == text[i - 1]) and dp[i - 1][j]) dp[i][j] = dp[i][j - 2]
if pattern[j - 2] == "." or pattern[j - 2] == text[i - 1]:
dp[i][j] |= dp[i - 1][j]
else: else:
dp[i][j] = False dp[i][j] = False