|
|
<!DOCTYPE HTML>
|
|
|
<html lang="zh-CN" class="light sidebar-visible" dir="ltr">
|
|
|
<head>
|
|
|
<!-- Book generated using mdBook -->
|
|
|
<meta charset="UTF-8">
|
|
|
<title>双单向链表 - Rust语言圣经(Rust Course)</title>
|
|
|
|
|
|
|
|
|
<!-- Custom HTML head -->
|
|
|
|
|
|
<meta name="description" content="">
|
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|
|
<meta name="theme-color" content="#ffffff">
|
|
|
|
|
|
<link rel="icon" href="../../favicon.svg">
|
|
|
<link rel="shortcut icon" href="../../favicon.png">
|
|
|
<link rel="stylesheet" href="../../css/variables.css">
|
|
|
<link rel="stylesheet" href="../../css/general.css">
|
|
|
<link rel="stylesheet" href="../../css/chrome.css">
|
|
|
<link rel="stylesheet" href="../../css/print.css" media="print">
|
|
|
|
|
|
<!-- Fonts -->
|
|
|
<link rel="stylesheet" href="../../FontAwesome/css/font-awesome.css">
|
|
|
<link rel="stylesheet" href="../../fonts/fonts.css">
|
|
|
|
|
|
<!-- Highlight.js Stylesheets -->
|
|
|
<link rel="stylesheet" id="highlight-css" href="../../highlight.css">
|
|
|
<link rel="stylesheet" id="tomorrow-night-css" href="../../tomorrow-night.css">
|
|
|
<link rel="stylesheet" id="ayu-highlight-css" href="../../ayu-highlight.css">
|
|
|
|
|
|
<!-- Custom theme stylesheets -->
|
|
|
<link rel="stylesheet" href="../../theme/style.css">
|
|
|
|
|
|
|
|
|
<!-- Provide site root and default themes to javascript -->
|
|
|
<script>
|
|
|
const path_to_root = "../../";
|
|
|
const default_light_theme = "light";
|
|
|
const default_dark_theme = "navy";
|
|
|
</script>
|
|
|
<!-- Start loading toc.js asap -->
|
|
|
<script src="../../toc.js"></script>
|
|
|
</head>
|
|
|
<body>
|
|
|
<div id="body-container">
|
|
|
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
|
|
<script>
|
|
|
try {
|
|
|
let theme = localStorage.getItem('mdbook-theme');
|
|
|
let sidebar = localStorage.getItem('mdbook-sidebar');
|
|
|
|
|
|
if (theme.startsWith('"') && theme.endsWith('"')) {
|
|
|
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
|
|
}
|
|
|
|
|
|
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
|
|
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
|
|
}
|
|
|
} catch (e) { }
|
|
|
</script>
|
|
|
|
|
|
<!-- Set the theme before any content is loaded, prevents flash -->
|
|
|
<script>
|
|
|
const default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? default_dark_theme : default_light_theme;
|
|
|
let theme;
|
|
|
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
|
|
if (theme === null || theme === undefined) { theme = default_theme; }
|
|
|
const html = document.documentElement;
|
|
|
html.classList.remove('light')
|
|
|
html.classList.add(theme);
|
|
|
html.classList.add("js");
|
|
|
</script>
|
|
|
|
|
|
<input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
|
|
|
|
|
|
<!-- Hide / unhide sidebar before it is displayed -->
|
|
|
<script>
|
|
|
let sidebar = null;
|
|
|
const sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
|
|
|
if (document.body.clientWidth >= 1080) {
|
|
|
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
|
|
sidebar = sidebar || 'visible';
|
|
|
} else {
|
|
|
sidebar = 'hidden';
|
|
|
}
|
|
|
sidebar_toggle.checked = sidebar === 'visible';
|
|
|
html.classList.remove('sidebar-visible');
|
|
|
html.classList.add("sidebar-" + sidebar);
|
|
|
</script>
|
|
|
|
|
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
|
|
<!-- populated by js -->
|
|
|
<mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
|
|
|
<noscript>
|
|
|
<iframe class="sidebar-iframe-outer" src="../../toc.html"></iframe>
|
|
|
</noscript>
|
|
|
<div id="sidebar-resize-handle" class="sidebar-resize-handle">
|
|
|
<div class="sidebar-resize-indicator"></div>
|
|
|
</div>
|
|
|
</nav>
|
|
|
|
|
|
<div id="page-wrapper" class="page-wrapper">
|
|
|
|
|
|
<div class="page">
|
|
|
<div id="menu-bar-hover-placeholder"></div>
|
|
|
<div id="menu-bar" class="menu-bar sticky">
|
|
|
<div class="left-buttons">
|
|
|
<label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
|
|
<i class="fa fa-bars"></i>
|
|
|
</label>
|
|
|
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
|
|
<i class="fa fa-paint-brush"></i>
|
|
|
</button>
|
|
|
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
|
|
<li role="none"><button role="menuitem" class="theme" id="default_theme">Auto</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
|
|
</ul>
|
|
|
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
|
|
<i class="fa fa-search"></i>
|
|
|
</button>
|
|
|
</div>
|
|
|
|
|
|
<h1 class="menu-title">Rust语言圣经(Rust Course)</h1>
|
|
|
|
|
|
<div class="right-buttons">
|
|
|
<a href="../../print.html" title="Print this book" aria-label="Print this book">
|
|
|
<i id="print-button" class="fa fa-print"></i>
|
|
|
</a>
|
|
|
<a href="https://github.com/sunface/rust-course" title="Git repository" aria-label="Git repository">
|
|
|
<i id="git-repository-button" class="fa fa-github"></i>
|
|
|
</a>
|
|
|
<a href="https://github.com/sunface/rust-course/edit/main/src/too-many-lists/advanced-lists/double-singly.md" title="Suggest an edit" aria-label="Suggest an edit">
|
|
|
<i id="git-edit-button" class="fa fa-edit"></i>
|
|
|
</a>
|
|
|
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
<div id="search-wrapper" class="hidden">
|
|
|
<form id="searchbar-outer" class="searchbar-outer">
|
|
|
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
|
|
</form>
|
|
|
<div id="searchresults-outer" class="searchresults-outer hidden">
|
|
|
<div id="searchresults-header" class="searchresults-header"></div>
|
|
|
<ul id="searchresults">
|
|
|
</ul>
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
|
|
<script>
|
|
|
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
|
|
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
|
|
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
|
|
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
|
|
});
|
|
|
</script>
|
|
|
|
|
|
<div id="content" class="content">
|
|
|
<main>
|
|
|
<h1 id="双单向链表"><a class="header" href="#双单向链表">双单向链表</a></h1>
|
|
|
<p>在之前的双向链表章节中，我们一度非常纠结，原因来自同样纠结成一团的所有权依赖。还有一个重要原因就是：先入为主的链表定义。</p>
|
|
|
<p>谁说所有的链接一定要一个方向呢？这里一起来尝试下新的东东：链表的其中一半朝左，另一半朝右。</p>
|
|
|
<p>新规矩( 老规矩是创建文件 )，创建一个新的模块:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>// lib.rs
|
|
|
// ...
|
|
|
pub mod silly1; // NEW!
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>// silly1.rs
|
|
|
use crate::second::List as Stack;
|
|
|
|
|
|
struct List<T> {
|
|
|
left: Stack<T>,
|
|
|
right: Stack<T>,
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>这里将之前的 <code>List</code> 引入进来，并重命名为 <code>Stack</code>，接着，创建一个新的链表。现在既可以向左增长又可以向右增长。</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub struct Stack<T> {
|
|
|
head: Link<T>,
|
|
|
}
|
|
|
|
|
|
type Link<T> = Option<Box<Node<T>>>;
|
|
|
|
|
|
struct Node<T> {
|
|
|
elem: T,
|
|
|
next: Link<T>,
|
|
|
}
|
|
|
|
|
|
impl<T> Stack<T> {
|
|
|
pub fn new() -> Self {
|
|
|
Stack { head: None }
|
|
|
}
|
|
|
|
|
|
pub fn push(&mut self, elem: T) {
|
|
|
let new_node = Box::new(Node {
|
|
|
elem: elem,
|
|
|
next: self.head.take(),
|
|
|
});
|
|
|
|
|
|
self.head = Some(new_node);
|
|
|
}
|
|
|
|
|
|
pub fn pop(&mut self) -> Option<T> {
|
|
|
self.head.take().map(|node| {
|
|
|
let node = *node;
|
|
|
self.head = node.next;
|
|
|
node.elem
|
|
|
})
|
|
|
}
|
|
|
|
|
|
pub fn peek(&self) -> Option<&T> {
|
|
|
self.head.as_ref().map(|node| {
|
|
|
&node.elem
|
|
|
})
|
|
|
}
|
|
|
|
|
|
pub fn peek_mut(&mut self) -> Option<&mut T> {
|
|
|
self.head.as_mut().map(|node| {
|
|
|
&mut node.elem
|
|
|
})
|
|
|
}
|
|
|
}
|
|
|
|
|
|
impl<T> Drop for Stack<T> {
|
|
|
fn drop(&mut self) {
|
|
|
let mut cur_link = self.head.take();
|
|
|
while let Some(mut boxed_node) = cur_link {
|
|
|
cur_link = boxed_node.next.take();
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>稍微修改下 <code>push</code> 和 <code>pop</code>：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub fn push(&mut self, elem: T) {
|
|
|
let new_node = Box::new(Node {
|
|
|
elem: elem,
|
|
|
next: None,
|
|
|
});
|
|
|
|
|
|
self.push_node(new_node);
|
|
|
}
|
|
|
|
|
|
fn push_node(&mut self, mut node: Box<Node<T>>) {
|
|
|
node.next = self.head.take();
|
|
|
self.head = Some(node);
|
|
|
}
|
|
|
|
|
|
pub fn pop(&mut self) -> Option<T> {
|
|
|
self.pop_node().map(|node| {
|
|
|
node.elem
|
|
|
})
|
|
|
}
|
|
|
|
|
|
fn pop_node(&mut self) -> Option<Box<Node<T>>> {
|
|
|
self.head.take().map(|mut node| {
|
|
|
self.head = node.next.take();
|
|
|
node
|
|
|
})
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>现在可以开始构造新的链表:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub struct List<T> {
|
|
|
left: Stack<T>,
|
|
|
right: Stack<T>,
|
|
|
}
|
|
|
|
|
|
impl<T> List<T> {
|
|
|
fn new() -> Self {
|
|
|
List { left: Stack::new(), right: Stack::new() }
|
|
|
}
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>当然，还有一大堆左左右右类型的操作:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub fn push_left(&mut self, elem: T) { self.left.push(elem) }
|
|
|
pub fn push_right(&mut self, elem: T) { self.right.push(elem) }
|
|
|
pub fn pop_left(&mut self) -> Option<T> { self.left.pop() }
|
|
|
pub fn pop_right(&mut self) -> Option<T> { self.right.pop() }
|
|
|
pub fn peek_left(&self) -> Option<&T> { self.left.peek() }
|
|
|
pub fn peek_right(&self) -> Option<&T> { self.right.peek() }
|
|
|
pub fn peek_left_mut(&mut self) -> Option<&mut T> { self.left.peek_mut() }
|
|
|
pub fn peek_right_mut(&mut self) -> Option<&mut T> { self.right.peek_mut() }
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>其中最有趣的是：还可以来回闲逛了。</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub fn go_left(&mut self) -> bool {
|
|
|
self.left.pop_node().map(|node| {
|
|
|
self.right.push_node(node);
|
|
|
}).is_some()
|
|
|
}
|
|
|
|
|
|
pub fn go_right(&mut self) -> bool {
|
|
|
self.right.pop_node().map(|node| {
|
|
|
self.left.push_node(node);
|
|
|
}).is_some()
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>这里返回 <code>bool</code> 是为了告诉调用者我们是否成功的移动。最后，再来测试下：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>#[cfg(test)]
|
|
|
mod test {
|
|
|
use super::List;
|
|
|
|
|
|
#[test]
|
|
|
fn walk_aboot() {
|
|
|
let mut list = List::new(); // [_]
|
|
|
|
|
|
list.push_left(0); // [0,_]
|
|
|
list.push_right(1); // [0, _, 1]
|
|
|
assert_eq!(list.peek_left(), Some(&0));
|
|
|
assert_eq!(list.peek_right(), Some(&1));
|
|
|
|
|
|
list.push_left(2); // [0, 2, _, 1]
|
|
|
list.push_left(3); // [0, 2, 3, _, 1]
|
|
|
list.push_right(4); // [0, 2, 3, _, 4, 1]
|
|
|
|
|
|
while list.go_left() {} // [_, 0, 2, 3, 4, 1]
|
|
|
|
|
|
assert_eq!(list.pop_left(), None);
|
|
|
assert_eq!(list.pop_right(), Some(0)); // [_, 2, 3, 4, 1]
|
|
|
assert_eq!(list.pop_right(), Some(2)); // [_, 3, 4, 1]
|
|
|
|
|
|
list.push_left(5); // [5, _, 3, 4, 1]
|
|
|
assert_eq!(list.pop_right(), Some(3)); // [5, _, 4, 1]
|
|
|
assert_eq!(list.pop_left(), Some(5)); // [_, 4, 1]
|
|
|
assert_eq!(list.pop_right(), Some(4)); // [_, 1]
|
|
|
assert_eq!(list.pop_right(), Some(1)); // [_]
|
|
|
|
|
|
assert_eq!(list.pop_right(), None);
|
|
|
assert_eq!(list.pop_left(), None);
|
|
|
|
|
|
}
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<pre><code class="language-shell">$ cargo test
|
|
|
|
|
|
Running target/debug/lists-5c71138492ad4b4a
|
|
|
|
|
|
running 16 tests
|
|
|
test fifth::test::into_iter ... ok
|
|
|
test fifth::test::basics ... ok
|
|
|
test fifth::test::iter ... ok
|
|
|
test fifth::test::iter_mut ... ok
|
|
|
test fourth::test::into_iter ... ok
|
|
|
test fourth::test::basics ... ok
|
|
|
test fourth::test::peek ... ok
|
|
|
test first::test::basics ... ok
|
|
|
test second::test::into_iter ... ok
|
|
|
test second::test::basics ... ok
|
|
|
test second::test::iter ... ok
|
|
|
test second::test::iter_mut ... ok
|
|
|
test third::test::basics ... ok
|
|
|
test third::test::iter ... ok
|
|
|
test second::test::peek ... ok
|
|
|
test silly1::test::walk_aboot ... ok
|
|
|
|
|
|
test result: ok. 16 passed; 0 failed; 0 ignored; 0 measured
|
|
|
</code></pre>
|
|
|
<p>上上下下，左左右右，BABA，哦耶，这个链表无敌了！</p>
|
|
|
<p>以上是一个非常典型的<ruby>手指型数据结构<rt>finger data structure</rt></ruby>，在其中维护一个手指，然后操作所需的时间与手指的距离成正比。</p>
|
|
|
|
|
|
</main>
|
|
|
|
|
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|
|
<!-- Mobile navigation buttons -->
|
|
|
<a rel="prev" href="../../too-many-lists/advanced-lists/intro.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
|
<i class="fa fa-angle-left"></i>
|
|
|
</a>
|
|
|
|
|
|
<a rel="next prefetch" href="../../too-many-lists/advanced-lists/stack-allocated.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
|
<i class="fa fa-angle-right"></i>
|
|
|
</a>
|
|
|
|
|
|
<div style="clear: both"></div>
|
|
|
</nav>
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
|
|
<a rel="prev" href="../../too-many-lists/advanced-lists/intro.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
|
<i class="fa fa-angle-left"></i>
|
|
|
</a>
|
|
|
|
|
|
<a rel="next prefetch" href="../../too-many-lists/advanced-lists/stack-allocated.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
|
<i class="fa fa-angle-right"></i>
|
|
|
</a>
|
|
|
</nav>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<script>
|
|
|
window.playground_copyable = true;
|
|
|
</script>
|
|
|
|
|
|
<script src="../../ace.js"></script>
|
|
|
<script src="../../editor.js"></script>
|
|
|
<script src="../../mode-rust.js"></script>
|
|
|
<script src="../../theme-dawn.js"></script>
|
|
|
<script src="../../theme-tomorrow_night.js"></script>
|
|
|
|
|
|
<script src="../../elasticlunr.min.js"></script>
|
|
|
<script src="../../mark.min.js"></script>
|
|
|
<script src="../../searcher.js"></script>
|
|
|
|
|
|
<script src="../../clipboard.min.js"></script>
|
|
|
<script src="../../highlight.js"></script>
|
|
|
<script src="../../book.js"></script>
|
|
|
|
|
|
<!-- Custom JS scripts -->
|
|
|
<script src="../../assets/custom2.js"></script>
|
|
|
<script src="../../assets/bigPicture.js"></script>
|
|
|
|
|
|
|
|
|
</div>
|
|
|
</body>
|
|
|
</html>
|
