### pancakeSort 
from typing import *
def f_gold(arr: List[int]) -> List[int]:
    def reverse(arr, j):
        i = 0
        while i < j:
            arr[i], arr[j] = arr[j], arr[i]
            i, j = i + 1, j - 1
    n = len(arr)
    ans = []
    for i in range(n - 1, 0, -1):
        j = i
        while j > 0 and arr[j] != i + 1:
            j -= 1
        if j < i:
            if j > 0:
                ans.append(j + 1)
                reverse(arr, j)
            ans.append(i + 1)
            reverse(arr, i)
    return ans