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#12354. 计数序列

통계

给定四个整数 $m, b, c$ 和 $n$,计算满足以下条件的整数序列 $x_1, \dots, x_m$ 的数量:

  • $0 \le x_i \le b^i - c$;
  • $\sum_{i=1}^{m} x_i < n$。

输出答案对 $998\,244\,353$ 取模的结果。

输入格式

第一行包含三个整数 $m, b$ 和 $c$ ($1 \le m \le 50, 2 \le b \le 10^9, -b + 2 \le c \le b - 1$)。 第二行包含一个大整数 $n$ ($1 \le n \le b^{m+1}$)。

输出格式

输出一个整数:满足条件的序列数量对 $998\,244\,353$ 取模的结果。

样例

输入格式 1

2 3 1
5

输出格式 1

12

Editorials

IDTypeStatusTitlePosted ByLast UpdatedActions
#1818EditorialOpenNew Editorial for Problem #12354zrczrczrczrc2026-05-27 17:24:49View

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