Leetcode 367 Valid perfect square
[367. Valid perfect square]](https://leetcode.com/problems/valid-perfect-square/)
Leetcode 912 Sort an Array
Leetcode 1218 Longest Arithmetic Subsequence of Given Difference
1218. Longest Arithmetic Subsequence of Given Difference
The special case is
Depends on your implementation, the time for the init
to happen might need to be carefully thought of.