Define `flipdigits(x)` as the integer produced by reversing the decimal digits of non-negative integer `x` and removing leading zeroes from the reversed result. Examples: ```text flipdigits(5070) = 705 flipdigits(800) = 8 flipdigits(123) = 321 ``` Given an array `arr` of non-negative integers, count how many pairs `(i, j)` satisfy `i <= j` and: ```text arr[i] + flipdigits(arr[j]) = arr[j] + flipdigits(arr[i]) ``` Return the count as an integer. Example 1: ```text arr = [1, 20, 2, 11] output = 7 ``` Example 2: ```text arr = [32, 332, 100] output = 4 ``` Constraints: - `0 <= arr.length <= 100000` - `0 <= arr[i] <= 10^9` - Count pairs with `i <= j`, so each element pairs with itself.