Count Equal or One-Swap Number Pairs
Susquehanna International Group (SIG)● MediumFULLTIMEOAProblem statement
You are given an array of positive integers numbers. Count pairs of indices (i,j) with i < j such that the two values are equal, or one value can become the other by swapping exactly one pair of decimal digit positions in that one value.
Use the ordinary decimal representation of each number. A swap that places 0 in the leading position is invalid, so valid transformed numbers keep the same number of digits. You may not make one swap in each value.
Count each pair of indices once, even if several possible swaps produce the same value. Equal numbers at different indices count without a swap. Return the number of qualifying index pairs.
Function
countOneSwapPairs(numbers: int[]) → longExamples
Example 1
numbers = [1,23,156,1650,651,165,32]return = 3The qualifying value pairs are 23/32, 156/651 and 156/165. Transforming 1650 into 0651 is invalid because it creates a leading zero.
Example 2
numbers = [123,321,123]return = 3All three index pairs qualify: each 123 matches321 by one swap, and the two 123 values are equal.
Example 3
numbers = [1,10,100]return = 0Different digit lengths cannot be reconciled by a legal swap, so the count is 0.
Constraints
1 <= numbers.length <= 100000.1 <= numbers[i] <= 10^9.- Return a 64-bit integer count.