leetcode10. Regular Expression Matching

class Solution {
public:
    bool isMatch(string s, string p) {
        int m = s.length();
        int n = p.length();
        vector<vector<bool>> dp(n + 1, vector<bool>(m + 1, false));
        
        dp[0][0] = true;
        for (int i = 1; i <= n; i++)
        {
            if (p[i - 1] == '*')
                dp[i][0] = dp[i - 2][0];
        }
        
        for (int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= m; j++)
            {
                if (p[i - 1] == s[j - 1] || p[i - 1] == '.')
                    dp[i][j] = dp[i - 1][j - 1];
                else if (p[i - 1] == '*')
                    dp[i][j] = dp[i - 2][j] /*0*/ || dp[i - 1][j] /*1*/ || dp[i][j - 1] && (p[i - 2] == s[j - 1] || p[i - 2] == '.');
            }
        }
        
        return dp[n][m];
    }
};