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 <= 100Compiled with clang 11 using the latest C++ 20 standard.
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