Lexicographical Numbers – Python 3 (Week 13 – 03)

 class Solution:
    def lexicalOrder(self, n: int) -> List[int]:
        
        
        #1, 10, 11, 12, 13 ...,100,
        if n < 1:
            return []
        ans = [1]
        
        while len(ans) < n: #1
            new = ans[-1] * 10 #10
            while new > n:
                new //= 10 # new is ans[-1] 
                new += 1 #
                while new % 10 == 0: #not inclue 0, so 10, 100, 1000,
                    new //= 10 # until 2,3,4,5,...
                
            ans.append(new)  #10 if n is 11, 2 if n is 9 
                
            
        return ans