LeetCode 10 正则表达式匹配

Posted 2021-12-11 Starzkg

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

解决方案

class Solution {
    public boolean isMatch(String s, String p) {
        int m = s.length();
        int n = p.length();
        boolean[][] dp = new boolean[m + 1][n + 1];
        dp[0][0] = true;
        for (int i = 0; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if (p.charAt(j - 1) == '*') {
                    dp[i][j] = dp[i][j - 2];
                    if (i != 0 && matches(s.charAt(i - 1), p.charAt(j - 2))) {
                        dp[i][j] = dp[i][j] | dp[i - 1][j];
                    }
                } else {
                    if (i != 0 && matches(s.charAt(i - 1), p.charAt(j - 1))) {
                        dp[i][j] = dp[i - 1][j - 1];
                    }
                }
            }
        }
        return dp[m][n];
    }

    public boolean matches(char s, char p) {
        return (p == '.' || s == p);
    }

}