[Leetcode] 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:
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

碉堡了，可以用动规，但是如果存储n*m的表的话会爆内存，可以用2*m的表存，也可以回溯法，存储star的位置，后面不匹配的话就回退到star的位置重新匹配。

class Solution {
//if strlen is used, then it will be TLE
//iteration based solution
public:
    bool isMatch(const char *s, const char *p) {
        bool star = false;
        const char *starPos = NULL;
        const char *savePos = NULL;
        while (*s != '') {
            if (*p == '?') {
                ++p; ++s;
            } else if (*p == '*') {
                while (*p == '*') ++p;
                star = true;
                starPos = p;
                savePos = s;
            } else {
                if (*p == *s) {
                    ++p; ++s;
                } else {
                    if (star) {
                        s = ++savePos;
                        p = starPos;
                    } else {
                        return false;
                    }
                }
            }
        }
        while (*p == '*') ++p;
        return (*s == '') && (*p == '');
    }
};