CF494B.Obsessive String

普及/提高-

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题目描述

Hamed has recently found a string tt and suddenly became quite fond of it. He spent several days trying to find all occurrences of tt in other strings he had. Finally he became tired and started thinking about the following problem. Given a string ss how many ways are there to extract k>=1k>=1 non-overlapping substrings from it such that each of them contains string tt as a substring? More formally, you need to calculate the number of ways to choose two sequences a1,a2,...,aka_{1},a_{2},...,a_{k} and b1,b2,...,bkb_{1},b_{2},...,b_{k} satisfying the following requirements:

  • k>=1k>=1
  • tt is a substring of string saisai+1...sbis_{ai}s_{ai}+1... s_{bi} (string ss is considered as 11 -indexed).

As the number of ways can be rather large print it modulo 109+710^{9}+7 .

输入格式

Input consists of two lines containing strings ss and tt ( 1<=s,t<=1051<=|s|,|t|<=10^{5} ). 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
    
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