blocks|key|2355931|text|作为stated+in+the+comments，该标准没有为许多basic_string函数(包括erase)指定任何复杂性要求。这在一定程度上是因为历史上有许多不同的实现策略(最著名的是，写入时复制在C%2B%2B98时代很流行)，所以委员会不愿太精确地指定任何东西。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2355932|典型的现代实现的basic+behavior非常类似于vector<char>：插入和删除在结束时很便宜(通过分期重新分配)，在开始时很昂贵。处理小字符串时根本不需要内存分配(通过重用指针的空间来存储字符)。这意味着，如果字符串变得非常短，擦除可能会导致复制整个字符串(但复制成本很低)。这也意味着迭代器和引用是无效的比vector更容易。|BOLD|2355933|没有任何算法在string上执行得更好，但是有一些替代的数据结构具有不同的性能特征。rope的典型之处在于，它提供的访问速度稍慢，但插入和删除速度要快得多。|2355934|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/52866539/c-time-and-space-complexity-of-string-class-erase-member-function#comment92646918_52866539|1|https://en.wikipedia.org/wiki/Rope_(data_structure)^0|X|C|1E|5|2|M|0|0|8|E|4C|3|R|C|4G|6|0|7|6|S|4|16|4|1|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|F|3|G|5|6|7|12|8|@$9|13|A|14|B|H]|$9|15|A|16|B|H]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|I|3|J|5|6|7|1B|8|@$9|1C|A|1D|B|C]|$9|1E|A|1F|B|H]]|D|@$9|1G|A|1H|1|1I]]|E|$]]|$1|K|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]|S|$5|N|O|P|E|$Q|T]]]]

As <a href="https://stackoverflow.com/questions/52866539/c-time-and-space-complexity-of-string-class-erase-member-function#comment92646918_52866539">stated in the comments</a>, the standard doesn't specify any complexity requirements for many <code>basic_string</code> functions (including <code>erase</code>). This is partly because there have historically been a number of different implementation strategies (most famously, copy-on-write was popular in the C++98 era), so the committee was reluctant to specify anything too precisely.

The basic behavior of typical, modern implementations is very much like <code>vector&lt;char&gt;</code>: insertion and deletion are cheap at the end (with amortized reallocations) and expensive at the beginning. Small strings are handled without memory allocation at all (by reusing the pointers' space to store the characters). This means that erasure can result in copying the whole string if it becomes very short (but then the copy is cheap). It also means that iterators and references are invalidated more easily than with <code>vector</code>.

There aren't any algorithms that perform better on a <code>string</code>, but there are alternate data structures that have different performance characteristics. The <a href="https://en.wikipedia.org/wiki/Rope_(data_structure)" rel="noreferrer">rope</a> is typical among these in that it provides somewhat slower access but much faster insertion and deletion.

I wanted to know if someone knew the implementation of the C++ string::erase function and it's complexity. I know the C++ string is an object of characters. I'm assuming it doesn't allocate and create a new object of characters and then copy over the characters from the old string O(n) and O(n) space. Does it shift over the characters O(n) and O(1) space? I've looked on cplusplus.com and Bjarne Stroustrup book but haven't been able to find the answer. Can someone point me to the source code where it's implemented or know the answer?

Thanks!

C++ Time and Space Complexity of string class erase member function

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我想知道是否有人知道C++ string::erase函数的实现以及它的复杂性。我知道C++字符串是一个字符对象。我假设它不会分配和创建一个新的字符对象，然后从旧的字符串O(n)和O(n)空间复制字符。它是否在字符O(n)和O(1)空间上移动？我看过cplusplus.com和Bjarne Stroustrup的书，但...

字符串类擦除成员函数的C++时空复杂度-腾讯云开发者社区-腾讯云

问字符串类擦除成员函数的C++时空复杂度
EN

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问字符串类擦除成员函数的C++时空复杂度EN

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问字符串类擦除成员函数的C++时空复杂度
EN