题解 | #正则表达式匹配#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param str string字符串 
     * @param pattern string字符串 
     * @return bool布尔型
     */
    bool match(string s, string p) {
        // write code here
        s = " " + s;
        p = " " + p;
        int n = s.length(), m = p.length();
        vector<vector<bool>> f(n + 1, vector<bool>(m + 1));
        f[0][0] = true;
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                if (s[i - 1] == p[j - 1] || p[j - 1] == '.') {
                    f[i][j] = f[i - 1][j - 1];
                } else if (p[j - 1] == '*') {
                    if (s[i - 1] != p[j - 2] && p[j - 2] != '.') {
                        f[i][j] = f[i][j - 2];
                    } else {
                        f[i][j] = f[i][j - 2] || f[i][j - 1] || f[i - 1][j];
                    }
                }
            }
        }
        return f[n][m];
    }
};