ruby, 28 bytes

Result

WA

Duration

1309ms

Code [DL]

puts$<.map{@1[/(.)\1 /?2:4]}

stdin

922 221
839 355
471 576
741 335
517 631
448 423
318 923
256 613
155 519
544 519
837 737
731 165
634 229
411 611
313 139
626 628
822 187
526 766
767 832
144 248
154 447
699 882
962 627
939 336
599 995
573 579
636 335
854 441
672 495
936 269
388 996
288 834

stdout

stderr

/volume/CODE:1: `@1' is not allowed as an instance variable name
puts$<.map{@1[/(.)\1 /?2:4]}
           ^
/volume/CODE:1: syntax error, unexpected integer literal, expecting '}'
puts$<.map{@1[/(.)\1 /?2:4]}
            ^
/volume/CODE:1: warning: regex literal in condition
/volume/CODE:1: syntax error, unexpected '}', expecting end-of-input
puts$<.map{@1[/(.)\1 /?2:4]}
                           ^

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7ffdd7acad80 /* 9 vars */) = 0
12    execve("/usr/local/ruby-2.7.1/bin/ruby", ["/usr/local/ruby-2.7.1/bin/ruby", "/volume/CODE"], 0x5589f359ed60 /* 9 vars */) = 0
11    execve("/bin/cat", ["cat", "-"], 0x5589f359ed40 /* 9 vars */) = 0
11    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=11, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
12    +++ exited with 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=1, si_utime=8, si_stime=1} ---
10    +++ exited with 1 +++