Implement regular expression matching with support for '.' and '*'.
'.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire input string (not partial). The function prototype should be: bool isMatch(const char *s, const char *p) Some examples: isMatch("aa","a") → false isMatch("aa","aa") → true isMatch("aaa","aa") → false isMatch("aa", "a*") → true isMatch("aa", ".*") → true isMatch("ab", ".*") → true isMatch("aab", "c*a*b") → true
public 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(s.length() < 1 || (p.charAt(0) != s.charAt(0)&&p.charAt(0)!='.')){ return false; } else{ return isMatch(s.substring(1),p.substring(1)); } } else{ int len = s.length(); int i = -1; while(i<len && (i<0 || p.charAt(0) == '.'|| p.charAt(0) == s.charAt(i))){ if(isMatch(s.substring(i+1),p.substring(2))){ return true; } i++; } return false; } } }