3265. Count Almost Equal Pairs I

You are given an array nums consisting of positive integers.

We call two integers x and y in this problem almost equal if both integers can become equal after performing the following operation at most once:

• Choose either x or y and swap any two digits within the chosen number.

Return the number of indices i and j in nums where i < j such that nums[i] and nums[j] are almost equal.

Note that it is allowed for an integer to have leading zeros after performing an operation.

Example 1:

Input: nums = [3,12,30,17,21]

Output: 2

Explanation:

The almost equal pairs of elements are:

• 3 and 30. By swapping 3 and 0 in 30, you get 3.
• 12 and 21. By swapping 1 and 2 in 12, you get 21.

Example 2:

Input: nums = [1,1,1,1,1]

Output: 10

Explanation:

Every two elements in the array are almost equal.

Example 3:

Input: nums = [123,231]

Output: 0

Explanation:

We cannot swap any two digits of 123 or 231 to reach the other.

Constraints:

• 2 <= nums.length <= 100
• 1 <= nums[i] <= 106