In Python a set is considered to be an unordered collection of unique elements. I found out about this method when solving the From 1967 to 2013 Problem on DMOJ. I actually wrote a different solution initially, one that iterated through 4 digits, comparing them to each other, but then I noticed that the input can go up to the tens of thousands. Also my submission only passed half the test cases😩.

I knew I needed a better way so I started researching and found the set() method. A set can be made from any iterable like a list, string or tuple and removes any duplicate values, which was perfect for this task.

I do feel like using set() is almost cheating here, as I generally avoid using “Python magic” to solve challenges, but this solution just looks so elegant. Anyways, here it is:

# 56 From 1987 to 2013 ccc13s1

def digit_same(year) -> bool:
    return len(set(year)) != len(year)

input_year = int(input())
year = str(input_year + 1)

while digit_same(year):       
    num_year = int(year)
    num_year += 1
    year = str(num_year)

print(year)