bash-pure, 79 bytes

Result

WA

Code [DL]

while read -n 1 c;do a[c]+=@;done
for i in {0..9};do echo -n ${a[c]//@/$i};done

stdin

2276145695905361933396863016857062505448639184469609260546557028944027306895743510421184507623541595

stdout

00000000000111111111112222222222233333333333444444444445555555555566666666666777777777778888888888899999999999

stderr

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

strace