[leetcode] Wildcard Matching

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
```

Dynamic programming approach. O(p*s*s) p is the length of patten, s is the length of string.

Time Limit Exceeded. I don’t think out better solution so far.

```class Solution {
public:
bool isMatch(string s, string p) {
//dp[i][j] stores whether patten[0~i] can match string[0~j - 1] dp[i][0] means whether patten[0~i] can match an empty string
//dp[i][j] = dp[i - 1][k] && isMatch(p[i], s[k+1~j]), k = 0, 1, 2, ..., j , when k is j , s[k+1~j] means an empty string
if(p.size() == 0 && s.size() == 0) return true;
if(p.size() == 0) return false;//p.size() == 0 && s.size() > 0
bool dp[p.size()][s.size() + 1];
//memset(dp, false, sizeof(dp));
for(int i = 0; i < s.size() + 1; i++){
//initialize
char patten = p[0];
dp[0][i] = isMatchChar(s.substr(0, i), patten);
}
for(int i = 1; i < p.size(); i++){
for(int j = 0; j < s.size() + 1; j++){
//populate the dp array
for(int k = 0; k <= j; k++){
dp[i][j] = dp[i - 1][k] && isMatchChar(s.substr(k, j - k), p[i]);
if(dp[i][j]){
break;//
}
}
}
}
return dp[p.size() - 1][s.size()];
}
bool isMatchChar(string s, char p){
if(p == '*') return true;
if(p == '?' && s.size() == 1) return true;
if(s.size() == 1 && p == s[0]) return true;
return false;
}
};```

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