{ "data": { "question": { "questionId": "1885", "questionFrontendId": "1759", "boundTopicId": null, "title": "Count Number of Homogenous Substrings", "titleSlug": "count-number-of-homogenous-substrings", "content": "

Given a string s, return the number of homogenous substrings of s. Since the answer may be too large, return it modulo 109 + 7.

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A string is homogenous if all the characters of the string are the same.

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A substring is a contiguous sequence of characters within a string.

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Example 1:

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\r\nInput: s = "abbcccaa"\r\nOutput: 13\r\nExplanation: The homogenous substrings are listed as below:\r\n"a"   appears 3 times.\r\n"aa"  appears 1 time.\r\n"b"   appears 2 times.\r\n"bb"  appears 1 time.\r\n"c"   appears 3 times.\r\n"cc"  appears 2 times.\r\n"ccc" appears 1 time.\r\n3 + 1 + 2 + 1 + 3 + 2 + 1 = 13.
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Example 2:

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\r\nInput: s = "xy"\r\nOutput: 2\r\nExplanation: The homogenous substrings are "x" and "y".
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Example 3:

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\r\nInput: s = "zzzzz"\r\nOutput: 15\r\n
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Constraints:

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