Your music player contains n different songs. You want to listen to goal songs (not necessarily different) during your trip. To avoid boredom, you will create a playlist so that:
k other songs have been played.Given n, goal, and k, return the number of possible playlists that you can create. Since the answer can be very large, return it modulo 109 + 7.
\n
Example 1:
\n\n\nInput: n = 3, goal = 3, k = 1\nOutput: 6\nExplanation: There are 6 possible playlists: [1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 1, 2], and [3, 2, 1].\n\n\n
Example 2:
\n\n\nInput: n = 2, goal = 3, k = 0\nOutput: 6\nExplanation: There are 6 possible playlists: [1, 1, 2], [1, 2, 1], [2, 1, 1], [2, 2, 1], [2, 1, 2], and [1, 2, 2].\n\n\n
Example 3:
\n\n\nInput: n = 2, goal = 3, k = 1\nOutput: 2\nExplanation: There are 2 possible playlists: [1, 2, 1] and [2, 1, 2].\n\n\n
\n
Constraints:
\n\n0 <= k < n <= goal <= 100你的音乐播放器里有 n 首不同的歌，在旅途中，你计划听 goal 首歌（不一定不同，即，允许歌曲重复）。你将会按如下规则创建播放列表：
k 首歌播放完之后才能再次播放。给你 n、goal 和 k ，返回可以满足要求的播放列表的数量。由于答案可能非常大，请返回对 109 + 7 取余 的结果。
示例 1：
\n\n\n输入：n = 3, goal = 3, k = 1\n输出：6\n解释：有 6 种可能的播放列表。[1, 2, 3]，[1, 3, 2]，[2, 1, 3]，[2, 3, 1]，[3, 1, 2]，[3, 2, 1] 。\n\n\n
示例 2：
\n\n\n输入：n = 2, goal = 3, k = 0\n输出：6\n解释：有 6 种可能的播放列表。[1, 1, 2]，[1, 2, 1]，[2, 1, 1]，[2, 2, 1]，[2, 1, 2]，[1, 2, 2] 。\n\n\n
示例 3：
\n\n\n输入：n = 2, goal = 3, k = 1\n输出：2\n解释：有 2 种可能的播放列表。[1, 2, 1]，[2, 1, 2] 。\n\n\n
\n\n
提示：
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