Leetcode #2553: Separate the Digits in an Array
In this guide, we solve Leetcode #2553 Separate the Digits in an Array in Python and focus on the core idea that makes the solution efficient.
You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.
Problem Statement
Given an array of positive integers nums, return an array answer that consists of the digits of each integer in nums after separating them in the same order they appear in nums. To separate the digits of an integer is to get all the digits it has in the same order.
Quick Facts
- Difficulty: Easy
- Premium: No
- Tags: Array, Simulation
Intuition
The rules are explicit, so simulating the process step by step is safest.
Careful state updates prevent subtle bugs.
Approach
Translate the rules into state updates and apply them in order.
Track the final state or aggregate as required.
Steps:
- Translate rules into state updates.
- Iterate for each step.
- Return the final state.
Example
Input: nums = [13,25,83,77]
Output: [1,3,2,5,8,3,7,7]
Explanation:
- The separation of 13 is [1,3].
- The separation of 25 is [2,5].
- The separation of 83 is [8,3].
- The separation of 77 is [7,7].
answer = [1,3,2,5,8,3,7,7]. Note that answer contains the separations in the same order.
Python Solution
class Solution:
def separateDigits(self, nums: List[int]) -> List[int]:
ans = []
for x in nums:
t = []
while x:
t.append(x % 10)
x //= 10
ans.extend(t[::-1])
return ans
Complexity
The time complexity is , and the space complexity is . The space complexity is .
Edge Cases and Pitfalls
Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.
Summary
This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.