Regular Expression Matching

https://leetcode.com/problems/regular-expression-matching/

class Solution {
public:
    bool isMatch(string s, string p) {
        int m = s.length();
        int n = p.length();
        vector<vector<bool>> dp(m+1, vector<bool>(n+1, false));
        dp[0][0] = 1;

        for(int i = 1; i<=n; i++)
        {
            if(p[i-1] == '*')
            {
                dp[0][i] = dp[0][i-2];
            }
        }

        for(int i = 1; i <= m; i++)
        {
            for(int j = 1; j <= n; j++)
            {
                if(s[i-1] == p[j-1] || p[j-1] == '.')
                {
                    dp[i][j] = dp[i-1][j-1];
                }
                else if(p[j-1] == '*')
                {
                    dp[i][j] = dp[i][j-2];

                    if(s[i-1] == p[j-2] || p[j-2] == '.')
                    {
                        dp[i][j] = dp[i][j] || dp[i-1][j];
                    }
                }
            }
        }

        return dp[m][n];
    }
};