Tricks for Competitive programming

IO

• Use Scanner directly and parse input step by step
• Use input! macro for any arbitrary inputs (Codeforces, Codechef requires this)
• Or, use Scanner or UnsafeScanner for parsing input on demand

dbg! macro

• dbg! is so handy, you can place it anywhere in the code, around a variable or even an expression, it outputs the value of expression to stderr. Great for debugging
• dbg!, when in doubt, pass the reference