EasyNo. 0989
Add to Array-Form of Integer — LeetCode 989 Python Solution
- Pattern
- Math and Number Theory
- Topics
- Array, Math
- Reading time
- 2 min
- Source
- leetcode.com
The problem
The array-form of an integer num is an array representing its digits in left to right order. For example, for num = 1321, the array form is [1,3,2,1].
Example
- Input
- num = [1,2,0,0], k = 34
- Output
- [1,2,3,4]
- Explanation
- 1200 + 34 = 1234
Python solution
class Solution:
def addToArrayForm(self, num: List[int], k: int) -> List[int]:
ans = []
i = len(num) - 1
while i >= 0 or k:
k += 0 if i < 0 else num[i]
k, x = divmod(k, 10)
ans.append(x)
i -= 1
return ans[::-1]Complexity
- Time
- O(n)where n is the length of num
- Space · auxiliary
- O(1)
Pattern: Math and Number Theory
Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 989. Add to Array-Form of Integer 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.
Related problems
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|---|---|---|
| 0048 | Rotate Image | Medium |
| 0066 | Plus One | Easy |
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| 0335 | Self Crossing | Hard |
| 0384 | Shuffle an Array | Medium |
Frequently asked questions
- How hard is LeetCode 989. Add to Array-Form of Integer?
LeetCode 989. Add to Array-Form of Integer is rated Easy on LeetCode.
- What is the time complexity of LeetCode 989. Add to Array-Form of Integer?
The Python solution on this page runs in O(n), where n is the length of \textit{num}.
- What is the space complexity of LeetCode 989. Add to Array-Form of Integer?
The Python solution on this page uses O(1) auxiliary space.
- What topics does LeetCode 989. Add to Array-Form of Integer cover?
LeetCode 989. Add to Array-Form of Integer is tagged Array and Math on LeetCode.