reasonml, 183 bytes

Result

WA

Duration

1032ms

Code [DL]

for (i in 0 to 31) {
  let a = Node.Fs.readFileSync("/dev/stdin", `utf8);
  if (a.[1] == a.[2]) {
    Js.log(String.sub(a, 2, 2));
  } else {
    Js.log(String.sub(a, 4, 4));
  };
};

stdin

494 416
929 824
386 684
447 778
688 186
489 987
266 167
332 828
934 292
426 227
982 847
633 331
266 628
211 681
372 334
139 341
515 243
894 665
522 244
345 456
542 644
242 323
675 224
133 887
436 331
499 991
588 554
476 767
335 551
939 929
417 466
177 658

stdout

stderr

  Warning number 35
  /tmp/code.re 1:1-8:1
  
  1 │ for (i in 0 to 31) {
  2 │   let a = Node.Fs.readFileSync("/dev/stdin", `utf8);
  . │ ...
  7 │   };
  8 │ };
  
  unused for-loop index i.
  internal/modules/cjs/loader.js:983
  throw err;
  ^

Error: Cannot find module 'bs-platform/lib/js/string.js'
Require stack:
- /tmp/code.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:980:15)
    at Function.Module._load (internal/modules/cjs/loader.js:862:27)
    at Module.require (internal/modules/cjs/loader.js:1042:19)
    at require (internal/modules/cjs/helpers.js:77:18)
    at Object.<anonymous> (/tmp/code.js:5:16)
    at Module._compile (internal/modules/cjs/loader.js:1156:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1176:10)
    at Module.load (internal/modules/cjs/loader.js:1000:32)
    at Function.Module._load (internal/modules/cjs/loader.js:899:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ '/tmp/code.js' ]
}

strace

10    execve("/bin/sh", ["/bin/sh", "/root/script", "/volume/CODE"], 0x7fffdd92c540 /* 9 vars */) = 0
11    execve("/usr/bin/realpath", ["realpath", "/volume/CODE"], 0x55c9f00edd18 /* 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/ln", ["ln", "-sf", "/volume/CODE", "/tmp/code.re"], 0x55c9f00edd38 /* 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("/usr/bin/bsc", ["/usr/bin/bsc", "/tmp/code.re"], 0x55c9f00edd20 /* 9 vars */) = 0
13    execve("/bin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fffa224ba50 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/local/sbin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fffa224ba50 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/local/bin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fffa224ba50 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/sbin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fffa224ba50 /* 9 vars */) = -1 ENOENT (No such file or directory)
13    execve("/usr/bin/node", ["node", "/usr/bin/bsc", "/tmp/code.re"], 0x7fffa224ba50 /* 9 vars */) = 0
20    execve("/usr/lib/node_modules/bs-platform/linux/bsc.exe", ["/usr/lib/node_modules/bs-platfor"..., "/tmp/code.re"], 0x55d6bdffef60 /* 9 vars */) = 0
21    execve("/bin/sh", ["sh", "-c", "/usr/lib/node_modules/bs-platfor"...], 0x7ffd69c91800 /* 9 vars */) = 0
21    execve("/usr/lib/node_modules/bs-platform/linux/refmt.exe", ["/usr/lib/node_modules/bs-platfor"..., "--print=binary", "/tmp/code.re"], 0x564d1b21d090 /* 9 vars */) = 0
21    +++ exited with 0 +++
20    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
20    +++ exited with 0 +++
13    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=20, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
18    +++ exited with 0 +++
17    +++ exited with 0 +++
16    +++ exited with 0 +++
15    +++ exited with 0 +++
14    +++ exited with 0 +++
19    +++ exited with 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=5, si_stime=1} ---
22    execve("/bin/cat", ["cat", "-"], 0x55c9f00edd38 /* 9 vars */ <unfinished ...>
23    execve("/usr/bin/node", ["/usr/bin/node", "/tmp/code.js"], 0x55c9f00edd48 /* 9 vars */) = 0
22    <... execve resumed>)             = 0
22    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=22, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
26    +++ exited with 0 +++
28    +++ exited with 0 +++
24    +++ exited with 0 +++
25    +++ exited with 0 +++
27    +++ exited with 0 +++
29    +++ exited with 1 +++
23    +++ exited with 1 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=23, si_uid=0, si_status=1, si_utime=3, si_stime=1} ---
30    execve("/bin/rm", ["rm", "/tmp/code.js", "/tmp/code.re"], 0x55c9f00edcf0 /* 9 vars */) = 0
30    +++ exited with 0 +++
10    --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=30, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
10    +++ exited with 0 +++