Number of Pairs of Strings With Concatenation Equal to Target
Given an array of digit strings nums and a digit string target, return the number of pairs of indices (i, j) where i != j such that the concatenation of nums[i] + nums[j] equals target.
Example 1
Input
nums = ["777","7","77","77"], target = "7777"Output
4Valid pairs are (0, 1), (1, 0), (2, 3), and (3, 2), whose concatenations all equal "7777".
Example 2
Input
nums = ["123","4","12","34"], target = "1234"Output
2Valid pairs are (0, 1) and (2, 3), whose concatenations equal "1234".
Constraints
- 2 <= nums.length <= 100
- 1 <= nums[i].length <= 100
- 2 <= target.length <= 100
- nums[i] and target consist of digits.
- nums[i] and target do not have leading zeros.