[LintCode] 正则表达式匹配

class Solution {
public:
    /**
     * @param s: A string 
     * @param p: A string includes "." and "*"
     * @return: A boolean
     */
    bool isMatch(const char *s, const char *p) {
        // write your code here
        int m = strlen(s), n = strlen(p);
        vector<vector<bool> > dp(m + 1, vector<bool> (n + 1, false));
        dp[0][0] = true;
        for (int j = 1; j <= n; j++)
            dp[0][j] = (j > 1 && p[j - 1] == '*' && dp[0][j - 2]);
        for (int j = 1; j <= n; j++) {
            for (int i = 1; i <= m; i++) {
                if (j > 1 && p[j - 1] == '*') 
                    dp[i][j] = dp[i][j - 2] || ((s[i - 1] == p[j - 2] || p[j - 2] == '.') && dp[i - 1][j]);
                else dp[i][j] = dp[i - 1][j - 1] && (s[i - 1] == p[j - 1] || p[j - 1] == '.');
            }
        }
        return dp[m][n];
    }
};