# Retain all records
@records[NR] = $*;
# Track max value of n
@maxn = max(@maxn, $n);

# After all records have been read, loop through retained records
# and print those with the max n value.
end {
  for (nr in @records) {
    map record = @records[nr];
    if (record["n"] == @maxn) {
      emit record;
    }
  }
}