How do you solve Remove Trailing Zeros From a String on LeetCode?

Remove Trailing Zeros From a String (LeetCode #2710) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(n) space complexity. Key insight: Trailing zeros can be removed by identifying the last non-zero character.

What is the brute force solution for Remove Trailing Zeros From a String?

The brute force approach for Remove Trailing Zeros From a String is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute force approach involves checking each character from the end of the string until we find a non-zero character. We can then slice the string to remove the trailing zeros. This is straightforward but not the most efficient. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Remove Trailing Zeros From a String?

Remove Trailing Zeros From a String uses the following concepts: String. The recommended patterns to study are: String Manipulation, Two Pointers.

What are the interview tips for Remove Trailing Zeros From a String?

Always clarify the constraints and edge cases with the interviewer. Discuss your thought process and why you choose a particular approach. Consider both time and space complexity when discussing your solution.

What are common mistakes when solving Remove Trailing Zeros From a String?

Not considering edge cases like all zeros or a single zero. Assuming string operations are always O(1) without realizing slicing can take O(n).

#2710

Remove Trailing Zeros From a String

Easy

StringString ManipulationTwo Pointers

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(n)
Space	O(1)	O(n)

💡

Intuition

Time O(n)Space O(n)

The optimal solution involves finding the last non-zero character in a single pass and slicing the string accordingly. This is efficient and avoids unnecessary operations.

⚙️

Algorithm

3 steps

1Step 1: Start from the end of the string and find the last non-zero character.
2Step 2: Use the index of this character to slice the string.
3Step 3: Return the sliced string as the result.

solution.py7 lines

1def remove_trailing_zeros(num):
2    index = len(num) - 1
3    while index >= 0 and num[index] == '0':
4        index -= 1
5    return num[:index + 1]
6
7print(remove_trailing_zeros('51230100'))

ℹ

Complexity note: The time complexity is O(n) because we traverse the string once, and slicing the string also takes O(n) in the worst case. However, we only do this once, making it efficient.

1Trailing zeros can be removed by identifying the last non-zero character.
2String slicing is a powerful tool in Python and other languages for manipulating strings.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.