{ "data": { "question": { "questionId": "115", "questionFrontendId": "115", "boundTopicId": null, "title": "Distinct Subsequences", "titleSlug": "distinct-subsequences", "content": "

Given two strings s and t, return the number of distinct subsequences of s which equals t.

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A string's subsequence is a new string formed from the original string by deleting some (can be none) of the characters without disturbing the remaining characters' relative positions. (i.e., "ACE" is a subsequence of "ABCDE" while "AEC" is not).

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The test cases are generated so that the answer fits on a 32-bit signed integer.

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Example 1:

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\nInput: s = "rabbbit", t = "rabbit"\nOutput: 3\nExplanation:\nAs shown below, there are 3 ways you can generate "rabbit" from S.\nrabbbit\nrabbbit\nrabbbit\n
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Example 2:

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\nInput: s = "babgbag", t = "bag"\nOutput: 5\nExplanation:\nAs shown below, there are 5 ways you can generate "bag" from S.\nbabgbag\nbabgbag\nbabgbag\nbabgbag\nbabgbag
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Constraints:

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