bash-pure, 107 bytes

Result

WA

Code [DL]

a=()
while read -n 1 c;do let a[c]++;done
for i in {0..10};do for j in {0..${a[i]}};do echo -n $i;done;done

stdin

2943360151764037451245418319355931092350994849655780418673972564478116162293747780335403471718668670

stdout

012345678910

stderr

/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

strace