my solution has time complexity of O(n*k) k = first k characters from a to z n = size of string but solution got TLE how to optimize it? link to the question and my solution:

https://codingcompetitions.withgoogle.com/kickstart/round/0000000000435c44/00000000007ebe5e

https://www.codechef.com/viewsolution/46839080

thanks in advance