you give binary string binary a subsequence binary consider good lead zero exception 0find number unique good subsequence binaryFor example binary 001 good subsequence 0 0 1 unique good subsequence 0 1 note subsequence 00 01 001 good lead zerosReturn number unique good subsequence binary since answer large return modulo 109 7a subsequence sequence derive sequence delete element change order remain element Example 1input binary 001output 2explanation the good subsequence binary 0 0 1the unique good subsequence 0 1example 2input binary 11output 2explanation the good subsequence binary 1 1 11the unique good subsequence 1 11example 3input binary 101Output 5explanation the good subsequence binary 1 0 1 10 11 101 the unique good subsequence 0 1 10 11 101 Constraints1 binarylength 105binary consist 0s 1s