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 entire input string (not partial).
The function prototype should be:
int matchedIdx(const char *s, const char *p)
Some examples:
matchedIdx("aa","a") → 0
matchedIdx("juliadntdas","a*nt") → 4
Thoughts:
- Similar to LeetCode: 44. Wildcard Matching, Wildcard Pattern Matching @ GeeksforGeeks and String Matching with Wildcards @ Hackerrank problem except here it is required to output the index of the first occurrence.
- Code
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;
}