https://codeforces.net/contest/1684/submission/157727918

this is my code for case

1

5 1

1 2 3 4 5

my code outputs 4 and the answer is 0 because you can move 5 to 0 yet, my code passed systest. in my code, if some number is maximum MEX and is given as input, it can't be detected as MEX.

i mean...this was very strange experience in my codeforces life.