44. WildCard Matching

Implement wildcard pattern matching with support for'?'and'*'.

'?' Matches any single character.
'*' Matches any sequence of characters (including the empty sequence).

The matching should cover the 
 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


  1. Keep track of last current input string position, current pattern string position and last asterisk (*) position.
  2. O(n + m) without extra space
  3. LeetCode: 44. Wildcard Matching, Wildcard Pattern Matching @ GeeksforGeeks and String Matching with Wildcards @ Hackerrank

Code (C):

 bool isMatch(const char *s, const char *p) {
        const char* star=NULL;
        const char* ss=s;
        while (*s){
            //advancing both pointers when (both characters match) or ('?' found in pattern)
            //note that *p will not advance beyond its length 
            if ((*p=='?')||(*p==*s)){s++;p++;continue;} 

            // * found in pattern, track index of *, only advancing pattern pointer 
            if (*p=='*'){star=p++; ss=s;continue;} 

            //current characters didn't match, last pattern pointer was *, current pattern pointer is not *
            //only advancing pattern pointer
            if (star){ p = star+1; s=++ss;continue;} 

           //current pattern pointer is not star, last patter pointer was not *
           //characters do not match
            return false;

       //check for remaining characters in pattern
        while (*p=='*'){p++;}

        return !*p;  


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