秋招模拟赛第41场|2023.08.27-字节跳动秋招第二场
- Status
- Done
- Rule
- IOI
- Problem
- 4
- Start at
- 2023-9-8 19:00
- End at
- 2023-9-8 21:00
- Duration
- 2 hour(s)
- Host
- Partic.
- 38
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给定一个只含数字的字符串, 例如1233 , 其奇数位的数位和为:1+3=4 , 偶数位的数位和位2+3=5 (奇数位指下标是奇数的位置,偶数位指下标是偶数的位置,下标从1开始。)
奇偶权值f(s)为:奇数位的和乘以偶数位的和。 f(1233)=4∗5=20
请计算所有长度为n的数字串(可以有前导零)的奇偶权值的和是多少?
一行正整数n≤1e9
输出一个非负整数,表示权值和。
答案可能太大,请对109+7取模后再输出。
输入
2
输出
2025
输入
3
输出
40500
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