Problem: 1927B - Following the String

My 1st approach:277732437 — Gave TLE on test 3

Read editorial, understood that their approach was similar but they did not store the alphabets, they only stored the count.

2nd submission after reading editorial:277733314 — Still gave TLE on test 3

Tried to submit the exact code given in the editorial(277733398) — Still gave TLE on test 3

Can someone please suggest a better way of solving it?(I went through a few submissions but they did the same thing and got AC so i was confused about what was wrong in my submissions)(Or some of the other submissions which were different, i could not exactly grasp what they were trying to do/what approach they followed)