A12594. Ehab and a Special Coloring Problem
编程题
普及/提高-
知识点
题目描述
You're given an integer $n$ . For every integer $i$ from $2$ to $n$ , assign a positive integer $a_i$ such that the following conditions hold:
- For any pair of integers $(i,j)$ , if $i$ and $j$ are coprime, $a_i \neq a_j$ .
- The maximal value of all $a_i$ should be minimized (that is, as small as possible).
A pair of integers is called [coprime](https://en.wikipedia.org/wiki/Coprime_integers) if their [greatest common divisor](https://en.wikipedia.org/wiki/Greatest_common_divisor) is $1$ .
- For any pair of integers $(i,j)$ , if $i$ and $j$ are coprime, $a_i \neq a_j$ .
- The maximal value of all $a_i$ should be minimized (that is, as small as possible).
A pair of integers is called [coprime](https://en.wikipedia.org/wiki/Coprime_integers) if their [greatest common divisor](https://en.wikipedia.org/wiki/Greatest_common_divisor) is $1$ .
输入格式
The only line contains the integer $n$ ( $2 \le n \le 10^5$ ).
输出格式
Print $n-1$ integers, $a_2$ , $a_3$ , $\ldots$ , $a_n$ ( $1 \leq a_i \leq n$ ).
If there are multiple solutions, print any of them.
If there are multiple solutions, print any of them.
输入输出样例
输入 #1
4
输出 #1
1 2 1
输入 #2
3
输出 #2
2 1
说明/提示
In the first example, notice that $3$ and $4$ are coprime, so $a_3 \neq a_4$ . Also, notice that $a=[1,2,3]$ satisfies the first condition, but it's not a correct answer because its maximal value is $3$ .