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1291. Sequential Digits

Difficulty Topics

Description

An integer has sequential digits if and only if each digit in the number is one more than the previous digit.

Return a sorted list of all the integers in the range [low, high] inclusive that have sequential digits.

 

Example 1:

Input: low = 100, high = 300
Output: [123,234]

Example 2:

Input: low = 1000, high = 13000
Output: [1234,2345,3456,4567,5678,6789,12345]

 

Constraints:

  • 10 <= low <= high <= 10^9

Solution

sequential-digits.py
class Solution:
    def sequentialDigits(self, low: int, high: int) -> List[int]:

        q = collections.deque(range(1,10))
        res = []

        while q:
            v = q.popleft()
            if low <= v <= high:
                res.append(v)

            last = v%10

            if last < 9:
                q.append(v*10 + last + 1)

        return res