https://leetcode.com/problems/regular-expression-matching/

s50600822 · Dec 4, 2023 · 122c02a · 122c02a
1 parent 63b1cbf
commit 122c02a
Showing 1 changed file with 41 additions and 0 deletions.
diff --git a/interview_prep/algorithm/java/ide_handicapped/regular_expression_matching/Solution.java b/interview_prep/algorithm/java/ide_handicapped/regular_expression_matching/Solution.java
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+class Solution {
+    public boolean isMatch(String s, String p) {
+        int m = s.length(), n = p.length();
+        boolean[][] dp = new boolean[m + 1][n + 1];
+        dp[0][0] = true;
+
+        for (int i = 1; i <= m; i++) {
+            dp[i][0] = false;
+        }
+
+        for (int j = 1; j <= n; j++) {
+            if (p.charAt(j - 1) == '*') {
+                dp[0][j] = dp[0][j - 2];
+            } else {
+                dp[0][j] = false;
+            }
+        }
+
+        for (int i = 1; i <= m; i++) {
+            for (int j = 1; j <= n; j++) {
+                char sc = s.charAt(i - 1), pc = p.charAt(j - 1);
+                if (pc == '.') {
+                    dp[i][j] = dp[i - 1][j - 1];
+                } else if (pc == '*') {
+                    dp[i][j] = dp[i][j - 2] || ((sc == p.charAt(j - 2) || p.charAt(j - 2) == '.') && dp[i - 1][j]);
+                } else {
+                    dp[i][j] = (sc == pc) && dp[i - 1][j - 1];
+                }
+            }
+        }
+
+        return dp[m][n];
+    }
+
+    public static void main(String[] args) {
+        Solution self = new Solution();
+        assert self.isMatch("aa", "a") == false;
+        assert self.isMatch("aa", "a*") == true;
+        assert self.isMatch("aa", ".*") == true;
+    }
+}