We hope everyone had fun and enjoyed the contest!
Problem A — Catching the Impostor.
The problem is just implementation. Just check if exactly $$$n$$$ $$$-1$$$ numbers are encountered. You can easily do this using a set or a frequency array.
Problem B — Epic Permutation
Problem C — Similar Arrays
Problem D — Sanda's Job
Problem E — Count Substrings
Problem F — Game on Grid