Wildcard Matching leetcode java

描述
Implement wildcard pa�ern matching with support for '?' and '*'.
'?' Matches any single character. '*' Matches any sequence of characters (including the empty
sequence).
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", "*") → true
isMatch("aa", "a*") → true
isMatch("ab", "?*") → true
isMatch("aab", "c*a*b") → false

分析
跟上一题很类似。
主要是'*' 的匹配问题。p 每遇到一个'*'，就保留住当前'*' 的坐标和 s 的坐标，然后 s 从前
往后扫描，如果不成功，则 s++，重新扫描

代码

public class WildcardMatch {

    public static void main(String[] args) {
        // TODO Auto-generated method stu 
        String s= "aab";
        String p="*";
        System.out.println(isMatch(s,p));
    }
//    递归
        public static boolean isMatch(String s, String p) {
        if (p.length() == 0)
                return s.length() == 0;
            
        if (p.charAt(0) == '*') {    
                
        while (p!=null&&p.startsWith("*")) {
            
            p=p.substring(1); //跳过*
        }    
        if (p==null) 
            return true;
        while (s!= null && !isMatch(s, p)) 
            s=s.substring(1);
        return s != null;
      }
      
        else if (p.charAt(0) == '' || s.charAt(0) == '') return p.charAt(0) == s.charAt(0);
        else if (p.charAt(0) == s.charAt(0) || p.charAt(0) == '?') {
            
            return isMatch(s.substring(1), p.substring(1));
        }
        else return false;
        }




//迭代版    
    public static boolean isMatch2(String s, String p) {  
        int i = 0;  
        int j = 0;  
        int star = -1;  
        int mark = -1;  
        while (i < s.length()) {  
            if (j < p.length()  
                    && (p.charAt(j) == '?' || p.charAt(j) == s.charAt(i))) {  
                ++i;  
                ++j;  
            } else if (j < p.length() && p.charAt(j) == '*') {  
                star = j++;  
                mark = i;  
            } else if (star != -1) {  
                j = star + 1;  
                i = ++mark;  
            } else {  
                return false;  
            }  
        }  
        while (j < p.length() && p.charAt(j) == '*') {  
            ++j;  
        }  
        return j == p.length();  
    }
}