{ "data": { "question": { "questionId": "2921", "questionFrontendId": "2801", "boundTopicId": null, "title": "Count Stepping Numbers in Range", "titleSlug": "count-stepping-numbers-in-range", "content": "

Given two positive integers low and high represented as strings, find the count of stepping numbers in the inclusive range [low, high].

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A stepping number is an integer such that all of its adjacent digits have an absolute difference of exactly 1.

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Return an integer denoting the count of stepping numbers in the inclusive range [low, high].

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Since the answer may be very large, return it modulo 109 + 7.

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Note: A stepping number should not have a leading zero.

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Example 1:

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\nInput: low = "1", high = "11"\nOutput: 10\nExplanation: The stepping numbers in the range [1,11] are 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. There are a total of 10 stepping numbers in the range. Hence, the output is 10.
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Example 2:

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\nInput: low = "90", high = "101"\nOutput: 2\nExplanation: The stepping numbers in the range [90,101] are 98 and 101. There are a total of 2 stepping numbers in the range. Hence, the output is 2.
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Constraints:

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