Merge pull request UTSAVS26#1025 from NK-Works/regular-exp

DP Hard: Regular Expression Matching

Algorithms_and_Data_Structures/Dynamic-Programming-Series/Hard-DP-Problems/regular-expression-matching.py

@@ -0,0 +1,24 @@
+def isMatch(s, p):
+    m, n = len(s), len(p)
+
+    # Initialize a (m+1) x (n+1) DP table
+    dp = [[False] * (n + 1) for _ in range(m + 1)]
+
+    dp[0][0] = True
+
+    for j in range(1, n + 1):
+        if p[j - 1] == '*':
+            dp[0][j] = dp[0][j - 2]
+
+    for i in range(1, m + 1):
+        for j in range(1, n + 1):
+            if p[j - 1] == s[i - 1] or p[j - 1] == '.':
+                dp[i][j] = dp[i - 1][j - 1]
+            elif p[j - 1] == '*':
+                dp[i][j] = dp[i][j - 2] or (dp[i - 1][j] and (p[j - 2] == s[i - 1] or p[j - 2] == '.'))
+
+    return dp[m][n]
+
+s = "aab"
+p = "c*a*b"
+print(f"Does '{s}' match the pattern '{p}': {isMatch(s, p)}")

Project-Structure.md

@@ -87,6 +87,8 @@
       * [Climbing-Stairs](Algorithms_and_Data_Structures/Dynamic-Programming-Series/Basic-DP-Problems/climbing-stairs.py)
       * [Fibonacci-Seq](Algorithms_and_Data_Structures/Dynamic-Programming-Series/Basic-DP-Problems/fibonacci-seq.py)
       * [House-Robber](Algorithms_and_Data_Structures/Dynamic-Programming-Series/Basic-DP-Problems/house-robber.py)
+    * Hard-Dp-Problems
+      * [Regular-Expression-Matching](Algorithms_and_Data_Structures/Dynamic-Programming-Series/Hard-DP-Problems/regular-expression-matching.py)
     * Medium-Dp-Problems
       * [Coin-Change](Algorithms_and_Data_Structures/Dynamic-Programming-Series/Medium-DP-Problems/coin-change.py)
       * [Longest-Inc-Subseq](Algorithms_and_Data_Structures/Dynamic-Programming-Series/Medium-DP-Problems/longest-inc-subseq.py)