Leetcode5762. 恰有 K 根木棍可以看到的排列数目(第一类斯特林数)

Posted 2021-06-07 ！0 ！

题目链接：https://leetcode-cn.com/problems/number-of-ways-to-rearrange-sticks-with-k-sticks-visible/

代码

class Solution {
    int N = 1010; 
    int MOD = 1000000007;
    int[][] f = new int[N][N];
    public int rearrangeSticks(int n, int k) {
        f[0][0] = 1;
        for (int i = 1; i <= n; i ++ )
            for (int j = 1; j <= k; j ++ )
                f[i][j] = (int)((f[i - 1][j - 1] + (long)(i - 1) * (f[i - 1][j])) % MOD);
        return f[n][k];
    }
}