Now 1 can be put anywhere any number of times in the R. So now R will convert to R = 1 ∗ 01 ∗ 01 ∗. Now we construct regex for any even number of 0. So we simply use the ‘star’ operator. and thus R = ( 1 ∗ 01 ∗ 01 ∗) ∗.
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