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const int N = 1e5 + 1, MOD = 1e9 + 7;
int next_idx[N][2];
int mem[N][2];
class Solution {
    int go(int i, bool found_one, const string &binary) {
        if (i == -1)
            return 0;
        int &ret = mem[i][found_one];
        if (~ret)
            return ret;
        found_one |= binary[i] == '1';
        ret = found_one;
        if (found_one || binary[i] == '1')
            ret += go(next_idx[i][0], found_one, binary);
        ret += go(next_idx[i][1], found_one, binary); 
        ret %= MOD;
        return ret;
    }
public:
    int numberOfUniqueGoodSubsequences(string binary) {
        int last_0 = -1, last_1 = -1;
        for (int i = binary.size() - 1; i >= 0; --i) {
            next_idx[i][0] = last_0;
            next_idx[i][1] = last_1;
            if (binary[i] == '1') {
                last_1 = i;
            } else {
                last_0 = i;
            }
        }
        memset(mem, -1, sizeof mem);
        return go(0, false, binary) + (last_0 != -1);
    }
};