Merge pull request #3727 from drxlx/0010-regular-expression-matching

Create 0010-regular-expression-matching.swift

Author: Ykhan799

swift/0010-regular-expression-matching.swift

@@ -0,0 +1,31 @@
+class Solution {
+    func isMatch(_ s: String, _ p: String) -> Bool {
+        let s = Array(s), p = Array(p)
+        var dp = [[Int]: Bool]()
+
+        func dfs(_ i: Int, _ j: Int) -> Bool {
+            if dp[[i, j]] != nil {
+                return dp[[i, j]]!
+            }
+            if i >= s.count && j >= p.count {
+                return true
+            }
+            if j >= p.count {
+                return false
+            }
+            let isMatch = i < s.count && (s[i] == p[j] || p[j] == ".")
+            if j + 1 < p.count && p[j + 1] == "*" {
+                dp[[i, j]] = dfs(i, j + 2) || (isMatch && dfs(i + 1, j))
+                return dp[[i, j]]!
+            }
+            if isMatch {
+                dp[[i, j]] = dfs(i + 1, j + 1)
+                return dp[[i, j]]!
+            }
+            dp[[i, j]] = false
+            return false
+        }
+        
+        return dfs(0, 0)
+    }
+}