Count Nice Pairs in an Array
You are given an array nums that consists of non-negative integers.
You are given an array nums that consists of non-negative integers. Let us define rev(x) as the reverse of the non-negative integer x. For example, rev(123) = 321, and rev(120) = 21. A pair of indices (i, j) is nice if it satisfies all of the following conditions:
Return the number of nice pairs of indices. Since that number can be too large, return it modulo 10^9 + 7.
Example 1
Input: nums = [42,11,1,97]
Output: 2
Explanation: The two pairs are: - (0,3) : 42 + rev(97) = 42 + 79 = 121, 97 + rev(42) = 97 + 24 = 121. - (1,2) : 11 + rev(1) = 11 + 1 = 12, 1 + rev(11) = 1 + 11 = 12.
Example 2
Input: nums = [13,10,35,24,76]
Output: 4
Constraints
- 1 <= nums.length <= 10^5
- 0 <= nums[i] <= 10^9
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