(\w)+\w*\1\w*
(\w)+(\w*\1){3}\w*
^1[10]*1$|^0[10]*0$
\b(?=\w*cat)\w{6}\b
\b(?=\w*bri)(?=\w*ing)\w{5,9}\b
\b(?!\w*cat)\w{6}\b
\b((\w)(?!\w*\2))*\b
^(?!.*10011)[01]*$
\w*(a[eiou]|e[aiou]|i[aeou]|o[aeiu]|u[aeio])\w*
^(?!.*1.1)[01]*$