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


第一遍：

public class Solution {
    public boolean isMatch(String s, String p) {
        if(p.length() == 0) return s.length() == 0;
        if(s.length() == 0) return p.length() == 0;
        if(p.charAt(0) == '?' || p.charAt(0) == s.charAt(0)) return isMatch(s.substring(1), p.substring(1));
        else if(p.charAt(0) == '*'){
            for(int i = 0; i < s.length(); i ++){
                if(isMatch(s.substring(i), p.substring(1))) return true;
            }
            return false;
        }
        else return false;
    }
}

Time Limit Exceeded

"abbabbbaabaaabbbbbabbabbabbbabbaaabbbababbabaaabbab", "*aabb***aa**a******aa*"

网上做法：

贪心的策略，能匹配就一直往后遍历，匹配不上了就看看前面有没有'*'来救救场，再从'*'后面接着试。

public class Solution {
    public boolean isMatch(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) == '*') {// i == s.length()
            ++j;
        }
        return j == p.length();
    }
}

 DP 解法： 但是会memory  limit exceeded：

public class Solution {
    public boolean isMatch(String s, String p) {
        if(p == null || p.length() == 0) return s == null || s.length() == 0;
        if(s == null || s.length() == 0){
            return p == null || p.length() == 0 || (p.charAt(0) == '*' && isMatch(s, p.substring(1)));
        }
        int plen = p.length();
        int slen = s.length();
        boolean[][] dp = new boolean[plen][slen];
        if(p.charAt(0) == s.charAt(0) || p.charAt(0) == '?' || p.charAt(0) == '*') dp[0][0] = true;
        for(int i = 1; i < plen; i ++){
            if(p.charAt(i) == '*') dp[i][0] = dp[i - 1][0];
            else break;
        }
        for(int j = 1; j < slen; j ++){
            if(p.charAt(0) == '*') dp[0][j] = dp[0][j - 1];
        }
        for(int i = 1; i < plen; i ++){
            for(int j = 1; j < slen; j ++){
                if(p.charAt(i) == '?' || p.charAt(i) == s.charAt(j)) dp[i][j] = dp[i - 1][j - 1];
                else if(p.charAt(i) == '*'){
                    dp[i][j] = dp[i - 1][j] || dp[i - 1][j - 1] || dp[i][j - 1];
                }else{
                    dp[i][j] = false;
                }
            }
        }
        return dp[plen - 1][slen - 1];
    }
}