#P494B. Obsessive String
Obsessive String
No submission language available for this problem.
Description
Hamed has recently found a string t and suddenly became quite fond of it. He spent several days trying to find all occurrences of t in other strings he had. Finally he became tired and started thinking about the following problem. Given a string s how many ways are there to extract k ≥ 1 non-overlapping substrings from it such that each of them contains string t as a substring? More formally, you need to calculate the number of ways to choose two sequences a1, a2, ..., ak and b1, b2, ..., bk satisfying the following requirements:
- k ≥ 1
- t is a substring of string saisai + 1... sbi (string s is considered as 1-indexed).
As the number of ways can be rather large print it modulo 109 + 7.
Input consists of two lines containing strings s and t (1 ≤ |s|, |t| ≤ 105). Each string consists of lowercase Latin letters.
Print the answer in a single line.
Input
Input consists of two lines containing strings s and t (1 ≤ |s|, |t| ≤ 105). Each string consists of lowercase Latin letters.
Output
Print the answer in a single line.
Samples
ababa
aba
5
welcometoroundtwohundredandeightytwo
d
274201
ddd
d
12