Turing Machine Part 5 — Twice as many ones as zeroes

This is the fifth part of the Turing Machine series. For your convenience you can find other parts in the table of contents in Part 1 – Addition

Today we check whether a string has exactly twice as many ones as zeroes.

States:

q0 - looking for the beginning
q1 - looking for 0
q2 - have 0, looking for end
q3 - looking for first 1
q4 - looking for second 1
q5 - checking for no 1
qyes - matches

The input looks like this:

$011$

Transition table:

$,q0,$,q1,R
^,q0,^,q0,L
0,q0,0,q0,L
1,q0,1,q0,L

0,q1,^,q2,R
1,q1,1,q1,R
^,q1,^,q1,R
$,q1,$,q5,L

0,q2,0,q2,R
1,q2,1,q2,R
^,q2,^,q2,R
$,q2,$,q3,L


0,q3,0,q3,L
1,q3,^,q4,L
^,q3,^,q3,L

0,q4,0,q4,L
1,q4,^,q0,L
^,q4,^,q4,L

^,q5,^,q5,L
$,q5,$,qyes,R