input -> alphabet (indexing starts from 1) -> output (index of the input number in alphabet) -> new alphabet (the number moved to the begin of the alphabet):

3 -> [1, 2, 3, 4, 5] -> 3 -> [3, 1, 2, 4, 5]
2 -> [3, 1, 2, 4, 5] -> 3 -> [2, 3, 1, 4, 5]
1 -> [2, 3, 1, 4, 5] -> 3 -> [1, 2, 3, 4, 5]
1 -> [1, 2, 3, 4, 5] -> 1 -> [1, 2, 3, 4, 5]
4 -> [1, 2, 3, 4, 5] -> 4 -> [4, 1, 2, 3, 5]
5 -> [4, 1, 2, 3, 5] -> 5 -> [5, 4, 1, 2, 3]

input: (n - number of numbers in alphabet, m - length of text to be encrypted, the text)

5, 6
3 2 1 1 4 5

Answer: 3 2 1 1 4 5 -> 3 3 3 1 4 5

Is there any data structure or algorithm to make this efficiently, faster than O(n*m)?
I'd be appreciated for any ideas. Thanks.