题目：

题解：

class Solution {
public:
    int findRotateSteps(string ring, string key) {
        int n = ring.size(), m = key.size();
        vector<int> pos[26];
        for (int i = 0; i < n; ++i) {
            pos[ring[i] - 'a'].push_back(i);
        }
        vector<vector<int>> dp(m, vector<int>(n, 0x3f3f3f3f));
        for (auto& i: pos[key[0] - 'a']) {
            dp[0][i] = min(i, n - i) + 1;
        }
        for (int i = 1; i < m; ++i) {
            for (auto& j: pos[key[i] - 'a']) {
                for (auto& k: pos[key[i - 1] - 'a']) {
                    dp[i][j] = min(dp[i][j], dp[i - 1][k] + min(abs(j - k), n - abs(j - k)) + 1);
                }
            }
        }
        return *min_element(dp[m - 1].begin(), dp[m - 1].end());
    }
};