Find Numbers with Even Number of Digits — LeetCode 1295 Python Solution

The problem

Given an array nums of integers, return how many of them contain an even number of digits.

Example

Input

nums = [12,345,2,6,7896]

Output

2

Explanation

12 contains 2 digits (even number of digits).

Python solution

class Solution:
    def findNumbers(self, nums: List[int]) -> int:
        return sum(len(str(x)) % 2 == 0 for x in nums)

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 1295. Find Numbers with Even Number of Digits is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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