#2801

Count Stepping Numbers in Range

international master · 2030 · lc hard +32 · verified · 27.8% accepted · 356 likes · top 6%

Description

Two positive integers low and high are given as strings. Count all stepping numbers in the inclusive range [low, high].

A stepping number is a positive integer in which every pair of adjacent digits differs by exactly 1.

Return the count modulo 10⁹ + 7.

Note: Stepping numbers must not have leading zeros.

Example 1:

Input: low = "1", high = "11"

Output: 10

Explanation: 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.

Example 2:

Input: low = "90", high = "101"

Output: 2

Explanation: 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.

Code

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class Solution:
    def countSteppingNumbers(self, low: str, high: str) -> int:

class Solution:
    def countSteppingNumbers(self, low: str, high: str) -> int: