“There is only one seven-digit number that has both these qualities: First, its digits are in ascending order in the sense that each digit after the first one (that is, the digit in the millions place) is greater than the digit before; and second, when it is multiplied by 2020, the resulting product Is a 10-digit number in which every digit from 0-9 appears once. That seven-digit number is the solution to the contest.”
Thanks to David Levine for bringing this puzzle to my attention
isAscendingNumber
containsAllDigits
solveContestProblem Authoring docs