In the last contest(Codeforces Round 976 (Div. 2)) E question I was up solving it and I was getting multiple TLEs and I saw a very similar code getting accepted The only difference was I was using my function for mod_mul instead of directly computing it in that line itself, I like to use those mod_mul,mod_add for better code readability
But in this question using those affected the verdict was it a one time thing or is it not advisable to use those functions how much difference does it actually take.
P.S Pasting both TLEd and Accepted solution for reference in case I misinterpreted something.