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You've decided to make up another string manipulation game instead of paying |
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attention in class. Starting with a string composed entirely of 'a' and 'b' |
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characters, you will iteratively apply the following operation: |
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For a string **s** of length **len**, choose indices **i** and **j**, where |
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**i** < **j** < **len**. Choose a character **c** that occurs in the substring |
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which begins at zero-based index **i** of string **s** and extends to the |
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index **j** (inclusive). Replace all characters in **s** with zero-based index |
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in [**i**, **j**] with a single instance of **c** to generate **s'**. Set |
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**s** to be **s'**. |
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As an example of sequence of operations consider the string 'abba'. Some of |
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the possible transformations are shown below. The substring being replaced is |
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enclosed in square brackets. |
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1. [abb]a β [aa] β a |
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2. a[bba] β [aa] β a |
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3. ab[ba] β [abb] β a |
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4. a[bb]a β aba |
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The goal of your game is simple: calculate how many different sequences of |
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operations you can perform. As this number can be very large, you decide to |
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calculate it modulo 1,000,000,007. Two sequences of operations are considered |
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different if they differ in length, or if they differ in at least one |
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position. Note that the order of operations is a factor. The empty sequence of |
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operations should be counted as well. Operations can be considered triples of |
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(**i**, **j**, **c**) as described above, and these are the only values used |
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when computing whether two operations are the same. |
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## Input |
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The first line of the input file contains a single number **N**, the number of |
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test cases. Each test case is written on a separate line, and contains a |
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string consisting of letters 'a' and 'b'. |
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## Output |
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Output N lines, with the answer to each test case on a single line. |
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## Constraints |
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**N** = 20 |
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1 β€ **len** β€ 60 |
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**s** only contains the lowercase characters 'a' and 'b'. |
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