AtCoder Beginner Contest 106
C
To Infinity
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原题
← BD →
翻译中…

Problem Statement

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Mr. Infinity has a string $S$ consisting of digits from 1 to 9. Each time the date changes, this string changes as follows:

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  • Each occurrence of 2 in $S$ is replaced with 22. Similarly, each 3 becomes 333, 4 becomes 4444, 5 becomes 55555, 6 becomes 666666, 7 becomes 7777777, 8 becomes 88888888 and 9 becomes 999999999. 1 remains as 1.
翻译中…

For example, if $S$ is 1324, it becomes 1333224444 the next day, and it becomes 133333333322224444444444444444 the day after next. You are interested in what the string looks like after $5 \times 10^{15}$ days. What is the $K$-th character from the left in the string after $5 \times 10^{15}$ days?

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Constraints

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  • $S$ is a string of length between $1$ and $100$ (inclusive).
  • $K$ is an integer between $1$ and $10^{18}$ (inclusive).
  • The length of the string after $5 \times 10^{15}$ days is at least $K$.
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Input

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Input is given from Standard Input in the following format:

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S
K

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Output

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Print the $K$-th character from the left in Mr. Infinity's string after $5 \times 10^{15}$ days.

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样例

Input #1
1214
4
Output #1
2
The string $S$ changes as follows: - Now: `1214` - After one day: `12214444` - After two days: `1222214444444444444444` - After three days: `12222222214444444444444444444444444444444444444444444444444444444444444444` The first five characters in the string after $5 \times 10^{15}$ days is `12222`. As $K=4$, we should print the fourth character, `2`.
Input #2
3
157
Output #2
3
The initial string is `3`. The string after $5 \times 10^{15}$ days consists only of `3`.
Input #3
299792458
9460730472580800
Output #3
2
题目信息
题号
abc106_c
时间限制
2 s
内存限制
976 MB

题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。