Regular Expression Matching

gistfile1.txt

public class Solution {
    public boolean isMatch(String s, String p) {
        // Start typing your Java solution below
        // DO NOT write main() function
        boolean[][] sol = new boolean[s.length() + 1][p.length() + 1];
        sol[0][0] = true;
        for (int i = 2; i <= p.length(); i++) {
            if (p.charAt(i - 1) == '*') {
                sol[0][i] = sol[0][i - 2];
            }
        }
        for (int i = 1; i <= s.length(); i++)
            for (int j = 1; j <= p.length(); j++) {
                if (p.charAt(j - 1) == '.' || p.charAt(j - 1) == s.charAt(i - 1)) {
                    sol[i][j] = sol[i - 1][j - 1];
                } else if (p.charAt(j - 1) == '*' && j > 1 && sol[i][j - 2]) {
                        sol[i][j] = true;
                } else if (p.charAt(j - 1) == '*' && (p.charAt(j - 2) == '.' || p.charAt(j - 2) == s.charAt(i - 1)))
                        sol[i][j] = sol[i - 1][j];
                }
            }
        return sol[s.length()][p.length()];
    }
}