Why I'm getting Compilation error on a same code? On this one 243516618, I use GNU G++17 7.3.0 and its totally okay and accepted also but when I submit 243516577 same code on GNU G++20 11.2.0 (64 bit, winlibs) language I got compilation error on this problem 1494A - ABC String. Why?

How does this code 226728618 run for this problem 121A - Lucky Sum even when I run for 1 to 1000000000 this testcase, my inner loop time complexity takes 1e9. Then how is it accepted?