Minimum Operations by Digit Reversal | Dataford Interview Questions

Given an integer array, find the minimum number of operations to make all numbers equal by reversing any digit.

In one operation, choose a distinct value and reverse the digits of every occurrence of that value. Return the minimum operations, or -1 if no common target is reachable. For example, [10, 1, 10] returns 1, because reversing the value 10 changes both occurrences to 1.

Input: a nonempty list nums of nonnegative integers. Output: an integer.

Examples: [12, 21, 12] returns 1; [7, 7, 7] returns 0.

Constraints: 1 <= len(nums) <= 1000, and 0 <= nums[i] <= 10^9.

Constraints

1 <= len(nums) <= 1000
0 <= nums[i] <= 10^9
An operation reverses every occurrence of one selected distinct value
Leading zeroes produced by reversal are discarded

Function Signature

def min_operations(nums):

Your question is Minimum Operations by Digit Reversal. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem