Talk:Next highest int from digits

Task development

I got the bare question from an SO question My original attempt at Algorithm1 failed as it relied of Pythons permutation generator generationg in sorted order from initially sorted digits - this only worked if there were no duplicated digits.

After fixing and manual testing I started on the second algorithm and used the following kind of loop to find errors: <lang python> for i in range(1_000):

       x = randint(10_000_000, 99_999_999)
       assert nexthigh1(x) == nexthigh(x), f"{x:>10} -> {nexthigh1(x):>10}, {nexthigh(x):>10}"

</lang>

My original closest_more_than() function was quite long, but explicit: <lang python>def closest_more_than2(n, lst):

   "(index of), closest int to digit n from lst that is > n"
   i, dif = None, None
   n = int(n)
   for j, val in enumerate(int(x) for x in lst):
       if val > n:
           inew, difnew = j, val - n
           if difnew == 1:
               return inew
           elif dif is None or dif > difnew:
               i, dif = inew, difnew
   return i

</lang> I had fun updating it, but needed the random test framework to flush out errors.
--Paddy3118 (talk) 11:12, 21 February 2020 (UTC)

Next_permutation

Someone on Reddit r/coding posted a cryptic `std::next_permutation()`. Some searching shows that if it produces the next lexicographic permutation thn it is doing all the heavy lifting! Try this explanation. --Paddy3118 (talk) 11:52, 21 February 2020 (UTC)