What is the main approach to solving "Remove Trailing Zeros From a String"?

The main approach involves string manipulation, specifically removing trailing zeros by iterating from the end of the string or using built-in methods like rstrip().

How do you handle strings with no trailing zeros?

If no trailing zeros are present, simply return the original string as no changes are necessary.

Can I use integer-based solutions for this problem?

No, the problem specifically requires working with a string representation, so integer-based solutions won't work for removing trailing zeros.

What if the input string contains only zeros?

In that case, the output should be "0", as a string of zeros should be reduced to a single zero.

What is the time complexity of the solution?

The time complexity is O(n), where n is the length of the string, as we must check each character from the end to the start.

#2710

Easy

auto_awesomeString-driven solution strategy

LeetCode 题解工作台

移除字符串中的尾随零

给你一个用字符串表示的正整数 num ，请你以字符串形式返回不含尾随零的整数 num 。示例 1：输入： num = "51230100" 输出： "512301" 解释：整数 "51230100" 有 2 个尾随零，移除并返回整数 "512301" 。示例 2：输入： num = "12…

字符串

题目描述

给你一个用字符串表示的正整数 num ，请你以字符串形式返回不含尾随零的整数 num 。

示例 1：

输入：num = "51230100"
输出："512301"
解释：整数 "51230100" 有 2 个尾随零，移除并返回整数 "512301" 。

示例 2：

输入：num = "123"
输出："123"
解释：整数 "123" 不含尾随零，返回整数 "123" 。

提示：

1 <= num.length <= 1000
num 仅由数字 0 到 9 组成
num 不含前导零

lightbulb

解题思路

方法一：遍历

我们可以从后往前遍历字符串，遇到第一个不是 0 的字符时停止遍历，然后返回从头开始到这个字符的子串。

时间复杂度 $O(n)$ ，其中 $n$ 是字符串的长度。忽略答案字符串的空间消耗，空间复杂度 $O(1)$ 。

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class Solution:
    def removeTrailingZeros(self, num: str) -> str:
        return num.rstrip("0")

speed

复杂度分析

指标	值
时间	Depends on the final approach
空间	Depends on the final approach

psychology

面试官常问的追问

外企场景

question_mark
Look for the candidate’s understanding of string manipulation and edge case handling.
question_mark
Evaluate how they handle the potential inefficiency of large string sizes.
question_mark
Test if they can provide a clear solution for non-zero trimming using string methods.

warning

常见陷阱

外企场景

error
Failing to handle edge cases where there are no trailing zeros.
error
Misunderstanding the requirement for string manipulation versus integer-based solutions.
error
Not considering the potential impact on performance with large strings.

swap_horiz

进阶变体

外企场景

arrow_right_alt
Consider variations where the input string contains only zeros.
arrow_right_alt
Explore edge cases where the number is a single-digit integer with no trailing zeros.
arrow_right_alt
Evaluate solutions that also account for leading zeros (if applicable in different scenarios).

help

常见问题

外企场景

继续练习

#2712 使所有字符相等的最小成本 #2707 字符串中的额外字符 #2716 最小化字符串长度