Add 10-Regular-Expression-Matching

java/10-Regular-Expression-Matching.java

@@ -0,0 +1,31 @@
+class Solution {
+
+ public boolean isMatch(String s, String p) {
+
+ boolean[][] cache = new boolean[s.length() + 1][p.length() + 1];
+
+ return dfs(cache , s, p, 0 , 0);
+ }
+
+ private boolean dfs(boolean[][] cache, String s, String p , int i, int j) {
+
+ if(cache[i][j] != false) 
+ return cache[i][j]; 
+
+ if( i >= s.length() && j>= p.length()) 
+ return true;
+
+ if(j >= p.length())
+ return false; 
+
+ boolean match = i < s.length() && (s.charAt(i) == p.charAt(j) || p.charAt(j) == '.');
+
+ if(j + 1 < p.length() && p.charAt(j+1)== '*' ) {
+ cache[i][j] = dfs(cache, s, p, i, j+2) || (match && dfs(cache, s, p, i+1, j));
+ } else {
+ cache[i][j] = match && dfs(cache, s, p, i+1, j+1);
+ }
+
+ return cache[i][j];
+ }
+}