bash-pure, 69 bytes

Result

AC

Duration

1407ms

Code [DL]

while read l;do
[ ${l:1:1} = ${l:2:1} ]&&a=1||a=4
echo ${l:$a:1}
done

stdin

791 517
139 396
133 641
211 112
676 876
373 531
158 827
685 221
261 169
414 114
411 339
668 843
164 145
924 228
578 552
966 264
522 767
988 886
397 936
637 981
147 771
767 269
561 143
932 237
529 645
331 358
256 567
577 173
964 442
599 957
299 339
899 921

stdout

5
3
3
1
8
5
8
2
1
1
1
8
1
2
5
6
2
8
9
9
7
2
1
2
6
3
5
7
4
9
9
9

stderr

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7fff6b08d750 /* 9 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55c0c279fd18 /* 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    execve("/bin/cp", ["cp", "-f", "/volume/CODE", "/opt/jails/bash-pure/code.bash"], 0x55c0c279fd58 /* 9 vars */) = 0
12    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
13    execve("/bin/cat", ["cat", "-"], 0x55c0c2f970d8 /* 9 vars */ <unfinished ...>
14    execve("/usr/sbin/jk_chrootlaunch", ["jk_chrootlaunch", "-j", "/opt/jails/bash-pure", "-x", "/bin/bash", "/code.bash"], 0x55c0c2f971c0 /* 9 vars */ <unfinished ...>
13    <... execve resumed>)             = 0
14    <... execve resumed>)             = 0
13    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=13, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
14    execve("/bin/bash", ["/bin/bash", "/code.bash"], 0x7ffc15c68240 /* 9 vars */) = 0
14    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=14, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
15    execve("/bin/rm", ["rm", "/opt/jails/bash-pure/code.bash"], 0x55c0c279fcb8 /* 9 vars */) = 0
15    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=15, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++