Regular Expression Matching
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) { // Start typing your Java solution below // DO NOT write main() function assert(p!=null && (p.length()==0 || p.charAt(0)!='*')); if(p.length()==0) return s.length()==0; if(p.length()==1 || p.charAt(1)!='*'){ if(s.length()<1 || (p.charAt(0)!='.' && p.charAt(0)!=s.charAt(0))) return false; return isMatch(s.substring(1),p.substring(1)); }else{ int i=-1; while(i<s.length() && (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; } } }
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