public class Solution
extends Object
786 - K-th Smallest Prime Fraction\.
Hard
You are given a sorted integer array `arr` containing `1` and **prime** numbers, where all the integers of `arr` are unique. You are also given an integer `k`.
For every `i` and `j` where `0 <= i < j < arr.length`, we consider the fraction `arr[i] / arr[j]`.
Return _the_ kth _smallest fraction considered_. Return your answer as an array of integers of size `2`, where `answer[0] == arr[i]` and `answer[1] == arr[j]`.
**Example 1:**
**Input:** arr = [1,2,3,5], k = 3
**Output:** [2,5]
**Explanation:**
The fractions to be considered in sorted order are:
1/5, 1/3, 2/5, 1/2, 3/5, and 2/3.
The third fraction is 2/5.
**Example 2:**
**Input:** arr = [1,7], k = 1
**Output:** [1,7]
**Constraints:**
* `2 <= arr.length <= 1000`
* 1 <= arr[i] <= 3 * 104
* `arr[0] == 1`
* `arr[i]` is a **prime** number for `i > 0`.
* All the numbers of `arr` are **unique** and sorted in **strictly increasing** order.
* `1 <= k <= arr.length * (arr.length - 1) / 2`