Problem B: Tight words
时间: 1ms 内存:128M
描述:
Problem B: Tight words
Given is an alphabet {0, 1, ... , k}, 0 <= k <= 9 . We say that a word of length n over this alphabet is tight if any two neighbour digits in the word do not differ by more than 1.
Input is a sequence of lines, each line contains two integer numbers k and n, 1 <= n <= 100. For each line of input, output the percentage of tight words of length n over the alphabet {0, 1, ... , k} with 5 fractional digits.
输入:
输出:
示例输入:
4 1
2 5
3 5
8 7
示例输出:
100.00000
40.74074
17.38281
0.10130
提示:
参考答案:
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