CF494B.Obsessive String
普及/提高-
通过率:0%
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题目描述
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 .
输入格式
Input consists of two lines containing strings s and t ( 1<=∣s∣,∣t∣<=105 ). Each string consists of lowercase Latin letters.
输出格式
Print the answer in a single line.
输入输出样例
输入#1
ababa aba
输出#1
5
输入#2
welcometoroundtwohundredandeightytwo d
输出#2
274201
输入#3
ddd d
输出#3
12