i430 区间dp

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//my
class Solution {
public:
    bool isScramble(string &s1, string &s2) {
        int m = s1.size(), n = s2.size();
        if (m != n)
            return false;
        vector>> dp(m, vector>(m, vector(m + 1, false)));
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < m; j++) {
                dp[i][j][1] = (s1[i] == s2[j]);
            }
        }

        for (int k = 2; k <= m; k++) {
            for (int i = 0; i <= m - k; i++) {
                for (int j = 0; j <= m - k; j++) {
                    for (int w = 1; w < k; w++) {
                        if (dp[i][j][w] && dp[i + w][j + w][k - w]) {
                            dp[i][j][k] = true;
                            break;
                        }
                        if (dp[i][j + k - w][w] && dp[i + w][j][k - w]) {
                            dp[i][j][k] = true;
                            break;
                        }
                    }
                }
            }
        }
        return dp[0][0][m];
    }
};