我觉得用perl写最简单
为求易读性所以我把许多perl magic都拿掉了
熟悉perl的话是可以把它写得更简洁的
#!/usr/bin/env perl
use 5.010;
do {
$_ = <STDIN>;
chomp $_; # chomp removes trailing \n
push @arr, $_;
} until ($_ =~ /flag/);
$flag = pop @arr; # the text match flag
$_ = <STDIN>; # obtain the next line after flag
print "$flag $_";
while ($_=<STDIN>) {
print ((shift @arr), " ", $_);
};