Created Regular_Expression_Matching.cpp

Dynamic_Programming/Regular_Expression_Matching.cpp

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+//Given a string s and a pattern p, implement regular expression matching with support for '.' (matches any single character) and '*' (zero or more of the preceding element).
+//Example:
+
+//Input: s = "mississippi", p = "mis*is*p*."
+//Output: false
+
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+bool isMatch(string s, string p) {
+    int m = s.size();
+    int n = p.size();
+    vector<vector<bool>> dp(m + 1, vector<bool>(n + 1, false));
+    dp[0][0] = true;
+
+    // Fill the first row
+    for (int j = 1; j <= n; ++j) {
+        if (p[j - 1] == '*') {
+            dp[0][j] = dp[0][j - 2];
+        }
+    }
+
+    // Fill the dp array using dynamic programming
+    for (int i = 1; i <= m; ++i) {
+        for (int j = 1; j <= n; ++j) {
+            if (p[j - 1] == s[i - 1] || p[j - 1] == '.') {
+                dp[i][j] = dp[i - 1][j - 1];
+            } else if (p[j - 1] == '*') {
+                dp[i][j] = dp[i][j - 2] || (dp[i - 1][j] && (s[i - 1] == p[j - 2] || p[j - 2] == '.'));
+            }
+        }
+    }
+
+    return dp[m][n];
+}
+
+int main() {
+    string s = "mississippi";
+    string p = "mis*is*p*.";
+    bool result = isMatch(s, p);
+    cout << "Matching result: " << (result ? "true" : "false") << endl;
+    return 0;
+}