How would you design a one-tape, two-head TM for checking tautonyms?

Question

I have to figure out if this language

L = { ww | w {0,1}*}

is decidable by a Turing machine. The TM has 1 tape and 2 heads/pointers. The input string is finite. Any suggestions on how to solve it ?

The way I see it, if I know the length of the string, it's easy to solve it.

This question appears to be off-topic because it is about theoretical CS, which is a better fit at cs.stackexchange.com. — templatetypedef, Jan 15 '15 at 17:45

score 0 · Accepted Answer · answered Jan 15 '15 at 17:45

As a hint, you can find the midpoint of the string by repeatedly moving one tape head two steps forward and the other one step forward until the faster tape head walks off the string; at that point, the slower tape head is at the halfway point. That might help you find the breakpoint in the string.

Hope this helps!

How would you design a one-tape, two-head TM for checking tautonyms?

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