From ba296e1e8923e09d539e0dad1931b279d5b7f09b Mon Sep 17 00:00:00 2001
From: AmirMohammad Hosseini Nasab <awmirhn@gmail.com>
Date: Fri, 12 Aug 2022 12:50:45 +0430
Subject: [PATCH 1/3] Add recursive solution to regex_match.py

---
 dynamic_programming/regex_match.py | 53 ++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 dynamic_programming/regex_match.py

diff --git a/dynamic_programming/regex_match.py b/dynamic_programming/regex_match.py
new file mode 100644
index 000000000000..b390d6eaef15
--- /dev/null
+++ b/dynamic_programming/regex_match.py
@@ -0,0 +1,53 @@
+"""
+Regex matching check if a text matches wildcard pattern or not.
+Pattern:
+    '.' Matches any single character.
+    '*' Matches zero or more of the preceding element.
+"""
+
+
+def recursive_match(text: str, pattern: str) -> bool:
+    """
+    Recursive matching algorithm.
+
+    Time complexity: O(2 ^ (m + n)), where m is the length of text and n is the length of pattern.
+    Space complexity: Recursion depth is O(m + n).
+
+    :param text: Text to match.
+    :param pattern: Pattern to match.
+    :return: True if text matches pattern, False otherwise.
+
+    >>> recursive_match('abc', 'a.c')
+    True
+    >>> recursive_match('abc', 'af*.c')
+    True
+    >>> recursive_match('abc', 'a.c*')
+    True
+    >>> recursive_match('abc', 'a.c*d')
+    False
+    """
+    if not text and not pattern:
+        return True
+
+    if text and not pattern:
+        return False
+
+    if not text and pattern and pattern[-1] != '*':
+        return False
+
+    if not text and pattern and pattern[-1] == '*':
+        return recursive_match(text, pattern[:-2])
+
+    if text[-1] == pattern[-1] or pattern[-1] == '.':
+        return recursive_match(text[:-1], pattern[:-1])
+
+    if pattern[-1] == '*':
+        return recursive_match(text[:-1], pattern) or recursive_match(text, pattern[:-2])
+
+    return False
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()

From 0cd88af4ff41118bc20b9971affb00b60b92dd5a Mon Sep 17 00:00:00 2001
From: AmirMohammad Hosseini Nasab <awmirhn@gmail.com>
Date: Fri, 12 Aug 2022 12:52:38 +0430
Subject: [PATCH 2/3] Add dp solution to regex_match.py

---
 dynamic_programming/regex_match.py | 47 ++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/dynamic_programming/regex_match.py b/dynamic_programming/regex_match.py
index b390d6eaef15..dc76eedebe60 100644
--- a/dynamic_programming/regex_match.py
+++ b/dynamic_programming/regex_match.py
@@ -25,6 +25,8 @@ def recursive_match(text: str, pattern: str) -> bool:
     True
     >>> recursive_match('abc', 'a.c*d')
     False
+    >>> recursive_match('aa', '.*')
+    True
     """
     if not text and not pattern:
         return True
@@ -47,6 +49,51 @@ def recursive_match(text: str, pattern: str) -> bool:
     return False
 
 
+def dp_match(text: str, pattern: str) -> bool:
+    """
+    Dynamic programming matching algorithm.
+
+    Time complexity: O(m * n), where m is the length of text and n is the length of pattern.
+    Space complexity: O(m * n).
+
+    :param text: Text to match.
+    :param pattern: Pattern to match.
+    :return: True if text matches pattern, False otherwise.
+
+    >>> dp_match('abc', 'a.c')
+    True
+    >>> dp_match('abc', 'af*.c')
+    True
+    >>> dp_match('abc', 'a.c*')
+    True
+    >>> dp_match('abc', 'a.c*d')
+    False
+    >>> dp_match('aa', '.*')
+    True
+    """
+    m = len(text)
+    n = len(pattern)
+    dp = [[False for _ in range(n + 1)] for _ in range(m + 1)]
+    dp[0][0] = True
+
+    for i in range(1, m + 1):
+        dp[i][0] = False
+
+    for j in range(1, n + 1):
+        dp[0][j] = pattern[j - 1] == '*' and dp[0][j - 2]
+
+    for i in range(1, m + 1):
+        for j in range(1, n + 1):
+            if pattern[j - 1] == '.' or pattern[j - 1] == text[i - 1]:
+                dp[i][j] = dp[i - 1][j - 1]
+            elif pattern[j - 1] == '*':
+                dp[i][j] = dp[i][j - 2] or (dp[i - 1][j] and (pattern[j - 2] == '.' or pattern[j - 2] == text[i - 1]))
+            else:
+                dp[i][j] = False
+
+    return dp[m][n]
+
+
 if __name__ == "__main__":
     import doctest
 

From 8d65acf76064ba8aaf87fe8087f2f4e10f053e76 Mon Sep 17 00:00:00 2001
From: AmirMohammad Hosseini Nasab <awmirhn@gmail.com>
Date: Fri, 12 Aug 2022 12:55:28 +0430
Subject: [PATCH 3/3] Add link to regex_match.py

---
 dynamic_programming/regex_match.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dynamic_programming/regex_match.py b/dynamic_programming/regex_match.py
index dc76eedebe60..bb2ed2d3a882 100644
--- a/dynamic_programming/regex_match.py
+++ b/dynamic_programming/regex_match.py
@@ -3,6 +3,8 @@
 Pattern:
     '.' Matches any single character.
     '*' Matches zero or more of the preceding element.
+More info:
+    https://medium.com/trick-the-interviwer/regular-expression-matching-9972eb74c03
 """