Recursive method:

class Solution {    public boolean isMatch(String s, String p) {        if (p.length() == 0) return s.length() == 0;                if (p.length() > 1 && p.charAt(1) == '*') {            if (isMatch(s, p.substring(2))) {                return true;            }                            if (s.length() > 0) {                return (s.charAt(0) == p.charAt(0) || p.charAt(0) == '.')  && isMatch(s.substring(1), p);            }        }                return s.length() > 0 && (s.charAt(0) == p.charAt(0) || p.charAt(0) == '.')  && isMatch(s.substring(1), p.substring(1));    }}

 

DP:

public class Solution {    public boolean isMatch(String s, String p) {       if (s == null || p == null) {           return false;       }        boolean[][] dp = new boolean[s.length() + 1][p.length() + 1];                dp[0][0] = true;        for (int i = 0; i < p.length(); i++) {            if (p.charAt(i) == '*' && dp[0][i-1]) {                dp[0][i+1] = true;            }        }                for (int i = 0; i < s.length(); i++) {            for (int j = 0; j < p.length(); j++) {                if (p.charAt(j) == '.' || p.charAt(j) == s.charAt(i)) {                    dp[i + 1][j + 1] = dp[i][j];                }                                if (p.charAt(j) == '*') {                    if (p.charAt(j - 1) != '.' && s.charAt(i) != p.charAt(j - 1)) {                        dp[i + 1][j + 1] = dp[i + 1][j - 1];                    } else {                        dp[i + 1][j + 1] = (dp[i + 1][j] || dp[i][j + 1] || dp[i + 1][j - 1]);                    }                }            }        }        return dp[s.length()][p.length()];    }}