You are given a string $s$ with length $N$ and in this problem you should find the number of **unique** **subsequences** (not substrings) of the string of every length.↵
eg. find the number of unique subsequences of length $1,$ then length $2, 3 ... N$. Answer can be big so print it modulo $1e9+7$. If the statement is confusing please, see the "explanations" below. I found [this post](https://www.geeksforgeeks.org/count-distinct-subsequences/) on geeksforgeeks but it counts the total number of distinct subsequences.↵
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Length of the string $N<=1000$↵
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#### Example:↵
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**Input:**↵
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$s = dpdp$↵
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**Output:**↵
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$2$ $4$ $4$ $1$↵
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**Explanation:**↵
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there are two subsequences of length 1: ${d, p}$↵
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4 subsequences of length 2: ${dp, dd, pd, pp}$↵
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4 subsequences of length 3: ${dpd, pdp, dpp, ddp}$↵
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1 subsequence of length 4: ${dpdp}$↵
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I think it's very easy problem but I have no idea how to solve it. Thanks in advance.↵
↵
Sorry for my poor English.
eg. find the number of unique subsequences of length $1,$ then length $2, 3 ... N$. Answer can be big so print it modulo $1e9+7$. If the statement is confusing please, see the "explanations" below. I found [this post](https://www.geeksforgeeks.org/count-distinct-subsequences/) on geeksforgeeks but it counts the total number of distinct subsequences.↵
↵
Length of the string $N<=1000$↵
↵
#### Example:↵
↵
**Input:**↵
↵
$s = dpdp$↵
↵
**Output:**↵
↵
$2$ $4$ $4$ $1$↵
↵
↵
**Explanation:**↵
↵
↵
there are two subsequences of length 1: ${d, p}$↵
↵
4 subsequences of length 2: ${dp, dd, pd, pp}$↵
↵
4 subsequences of length 3: ${dpd, pdp, dpp, ddp}$↵
↵
1 subsequence of length 4: ${dpdp}$↵
↵
I think it's very easy problem but I have no idea how to solve it. Thanks in advance.↵
↵
Sorry for my poor English.
