class Solution {
public:
    bool isScramble(string s1, string s2) {
        int n = s1.size();
        vector<vector<vector<bool>>> f(n, vector<vector<bool>>(n, vector<bool>(n + 1)));

        for (int len = 1; len <= n; ++len) {
            for (int i = 0; i + len - 1 < n; ++i ) {
                for (int j = 0; j + len - 1 < n; ++j) {
                    if (len == 1) {
                        if (s1[i] == s2[j]) {
                            f[i][j][len] = true;
                        }
                    } else {
                        for (int k = 1; k < len; ++k) {
                            if ((f[i][j][k] && f[i + k][j + k][len - k]) || (f[i][j + len - k][k] && f[i + k][j][len - k])) {
                                f[i][j][len] = true;
                                break;
                            }
                        }
                    }
                }
            }
        }

        return f[0][0][n];
    }
};