311 lines
35 KiB
HTML
311 lines
35 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
|
|
<head><meta http-equiv="x-ua-compatible" content="ie=edge">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<title>std::ranges::merge, std::ranges::merge_result</title>
|
|
<link rel="stylesheet" href="ext.css" />
|
|
<link rel="stylesheet" href="site_modules.css" />
|
|
</head>
|
|
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_algorithm_ranges_merge skin-cppreference2 action-view cpp-navbar">
|
|
<div id="cpp-content-base">
|
|
<div id="content"><a id="top"></a>
|
|
<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ranges::</span>merge, <span style="font-size:0.7em; line-height:130%">std::ranges::</span>merge_result</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-algorithm.html">algorithm</a>‎ | <a href="cpp-algorithm-ranges.html">ranges</a></span></div>
|
|
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
|
|
<table class="t-dcl-begin">
|
|
<tbody>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><a href="cpp-header-algorithm.html"><algorithm></a></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl-h">
|
|
<td>
|
|
<div>调用签名</div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx20">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> std<span class="sy4">::</span><span class="me2">input_iterator</span> I1, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I1<span class="sy1">></span> S1,<br /></span>
|
|
<p> std<span class="sy4">::</span><span class="me2">input_iterator</span> I2, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I2<span class="sy1">></span> S2,<br />
|
|
std<span class="sy4">::</span><span class="me2">weakly_incrementable</span> O, <span class="kw1">class</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span>,<br />
|
|
<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>, <span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span> <span class="sy1">></span><br />
|
|
requires std<span class="sy4">::</span><span class="me2">mergeable</span><span class="sy1"><</span>I1, I2, O, Comp, Proj1, Proj2<span class="sy1">></span><br />
|
|
<span class="kw4">constexpr</span> merge_result<span class="sy1"><</span>I1, I2, O<span class="sy1">></span><br />
|
|
merge<span class="br0">(</span> I1 first1, S1 last1, I2 first2, S2 last2, O result, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,<br /></p>
|
|
Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span><span class="sy4">;</span></div>
|
|
</td>
|
|
<td>(1)</td>
|
|
<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx20">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> ranges<span class="sy4">::</span><span class="me2">input_range</span> R1, ranges<span class="sy4">::</span><span class="me2">input_range</span> R2,<br /></span>
|
|
<p> std<span class="sy4">::</span><span class="me2">weakly_incrementable</span> O, <span class="kw1">class</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span>,<br />
|
|
<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>, <span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span> <span class="sy1">></span><br />
|
|
requires std<span class="sy4">::</span><span class="me2">mergeable</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R1<span class="sy1">></span>, ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R2<span class="sy1">></span>,<br />
|
|
O, Comp, Proj1, Proj2<span class="sy1">></span><br />
|
|
<span class="kw4">constexpr</span> merge_result<span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R1<span class="sy1">></span>,<br />
|
|
ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R2<span class="sy1">></span>, O<span class="sy1">></span><br />
|
|
merge<span class="br0">(</span> R1<span class="sy3">&&</span> r1, R2<span class="sy3">&&</span> r2, O result, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,<br /></p>
|
|
Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span><span class="sy4">;</span></div>
|
|
</td>
|
|
<td>(2)</td>
|
|
<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl-h">
|
|
<td>
|
|
<div>辅助类型</div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx20">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> I1, <span class="kw1">class</span> I2, <span class="kw1">class</span> O<span class="sy1">></span><br />
|
|
<span class="kw1">using</span> merge_result <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">in_in_out_result</span><span class="sy1"><</span>I1, I2, O<span class="sy1">></span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(3)</td>
|
|
<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>将两个<i>已排序</i>范围 <code>[first1, last1)</code> 和 <code>[first2, last2)</code> 归并为一个开始于 <code>result</code> 的<i>已排序</i>范围。</p>
|
|
<p>一个序列被称为关于 <code>comp</code> <i>已排序</i>，如果对于任何指向该序列的迭代器 <code>it</code> 和任何非负整数 <code>n</code> ，令 <code>it + n</code> 为一个指向该序列中的对象的有效迭代器， <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>comp, <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj2, <span class="sy2">*</span><span class="br0">(</span>it <span class="sy2">+</span> n<span class="br0">)</span><span class="br0">)</span>, <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj1, <span class="sy2">*</span>it<span class="br0">)</span><span class="br0">)</span><span class="br0">)</span></span></span> 等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">false</span></span></span> 。</p>
|
|
<div class="t-li1"><span class="t-li">1)</span> 用二元比较函数 <code>comp</code> 进行对象的比较。</div>
|
|
<div class="t-li1"><span class="t-li">2)</span> 同 <span class="t-v">(1)</span> ，但是以 <code>r1</code> 为第一个范围并以 <code>r2</code> 为第二个范围, 如同以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r1<span class="br0">)</span></span></span> 为 <code>first1</code> ，以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r1<span class="br0">)</span></span></span> 为 <code>last1</code> ，以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r2<span class="br0">)</span></span></span> 为 <code>first2</code> ，并以 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r2<span class="br0">)</span></span></span> 为 <code>last2</code> 。</div>
|
|
<p>若目标范围与任一输入范围重叠则行为未定义（输入范围可以彼此重叠）。</p>
|
|
<p>这个归并函数是 <i>稳定</i>的，意味着对于两个范围中的等价对象，来自第一个范围的对象(保持本身的排序状况) 将排在第二个范围当中的对象之前（保持其原先顺序）。</p>
|
|
<p>此页面上描述的仿函数实体是 <i>niebloid</i> ，即：</p>
|
|
<ul>
|
|
<li>调用它们中的任何一者时不可指定显式模板实参。</li>
|
|
<li>它们无一对<a href="cpp-language-adl.html">实参依赖查找</a>可见。</li>
|
|
<li>在<a href="cpp-language-unqualified_lookup.html">通常无限定查找</a>寻找函数调用运算符左侧的名称找到它们之一时，它禁止<a href="cpp-language-adl.html">实参依赖查找</a>。</li>
|
|
</ul>
|
|
<p>实际上，它们能以函数对象，或以某些特殊编译器扩展实现。</p>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
|
|
<table class="t-par-begin">
|
|
<tr class="t-par">
|
|
<td>first1, last1</td>
|
|
<td>-</td>
|
|
<td>第一已排序的输入范围</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>first2, last2</td>
|
|
<td>-</td>
|
|
<td>第二已排序的输入范围</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>result</td>
|
|
<td>-</td>
|
|
<td>输出范围的起始</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>comp</td>
|
|
<td>-</td>
|
|
<td>应用到投影后元素的比较器</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>proj1</td>
|
|
<td>-</td>
|
|
<td>应用到第一范围中元素的投影</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>proj2</td>
|
|
<td>-</td>
|
|
<td>应用到第二范围中元素的投影</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
|
|
<p><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">{</span>last1, last2, result_last<span class="br0">}</span></span></span>，其中 <span class="t-c"><span class="mw-geshi cpp source-cpp">result_last</span></span> 为被构造的范围末尾。</p>
|
|
<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">复杂度</span></h3>
|
|
<p>最多 <span class="t-c"><span class="mw-geshi cpp source-cpp">N−<span class="nu0">1</span></span></span> 次比较和投影的应用，其中 <span class="t-c"><span class="mw-geshi cpp source-cpp">N <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>first1, last1<span class="br0">)</span> <span class="sy2">+</span> ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>first2, last12<span class="br0">)</span></span></span>。</p>
|
|
<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">注解</span></h3>
|
|
<p>此算法进行与 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">set_union</span></span></span> 相似的任务。两者都使用两个已排序的范围产生一个包含两者的对象的已排序范围。两个算法的不同之处在于在两个输入范围当中的比较等价的值的处理方法（可以参考<a href="cpp-named_req-LessThanComparable.html"><span style="font-style:italic">可小于比较</span> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(LessThanComparable)</span></a> 上的注解）。如果任何相等的值出现了 <span class="t-c"><span class="mw-geshi cpp source-cpp">n</span></span> 次于第一个范围而 <span class="t-c"><span class="mw-geshi cpp source-cpp">m</span></span> 次于第二个， <span class="t-lc">ranges::merge</span> 将会输出全部的 <span class="t-c"><span class="mw-geshi cpp source-cpp">n<span class="sy2">+</span>m</span></span> 次出现，但是<span class="t-lc">ranges::set_union</span> 只会输出 <span class="t-c"><span class="mw-geshi cpp source-cpp">max<span class="br0">(</span>n, m<span class="br0">)</span></span></span> 次。所以 <span class="t-lc">ranges::merge</span> 输出恰好 <span class="t-c"><span class="mw-geshi cpp source-cpp">N</span></span> 个数值而 <span class="t-lc">ranges::set_union</span> 会输出更少。</p>
|
|
<h3><span class="mw-headline" id=".E5.8F.AF.E8.83.BD.E7.9A.84.E5.AE.9E.E7.8E.B0">可能的实现</span></h3>
|
|
<table class="eq-fun-cpp-table">
|
|
<tr>
|
|
<td>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="cpp source-cpp">
|
|
<pre class="de1"><span class="kw1">struct</span> merge_fn <span class="br0">{</span>
|
|
<span class="kw1">template</span><span class="sy1"><</span> std<span class="sy4">::</span><span class="me2">input_iterator</span> I1, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I1<span class="sy1">></span> S1,
|
|
std<span class="sy4">::</span><span class="me2">input_iterator</span> I2, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I2<span class="sy1">></span> S2,
|
|
std<span class="sy4">::</span><span class="me2">weakly_incrementable</span> O, <span class="kw1">class</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span>,
|
|
<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>, <span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span> <span class="sy1">></span>
|
|
requires std<span class="sy4">::</span><span class="me2">mergeable</span><span class="sy1"><</span>I1, I2, O, Comp, Proj1, Proj2<span class="sy1">></span>
|
|
<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">merge_result</span><span class="sy1"><</span>I1, I2, O<span class="sy1">></span>
|
|
operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span> I1 first1, S1 last1, I2 first2, S2 last2, O result, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,
|
|
Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
|
|
<span class="kw1">for</span> <span class="br0">(</span><span class="sy4">;</span> <span class="sy3">!</span><span class="br0">(</span>first1 <span class="sy1">==</span> last1 or first2 <span class="sy1">==</span> last2<span class="br0">)</span><span class="sy4">;</span> <span class="sy2">++</span>result<span class="br0">)</span> <span class="br0">{</span>
|
|
<span class="kw1">if</span> <span class="br0">(</span><a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>comp, <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj2, <span class="sy2">*</span>first2<span class="br0">)</span>, <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj1, <span class="sy2">*</span>first1<span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
|
|
<span class="sy2">*</span>result <span class="sy1">=</span> <span class="sy2">*</span>first2, <span class="sy2">++</span>first2<span class="sy4">;</span>
|
|
<span class="kw1">else</span>
|
|
<span class="sy2">*</span>result <span class="sy1">=</span> <span class="sy2">*</span>first1, <span class="sy2">++</span>first1<span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
<span class="kw4">auto</span> ret1 <span class="br0">{</span>ranges<span class="sy4">::</span><span class="me2">copy</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>first1<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>last1<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>result<span class="br0">)</span><span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
|
|
<span class="kw4">auto</span> ret2 <span class="br0">{</span>ranges<span class="sy4">::</span><span class="me2">copy</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>first2<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>last2<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>ret1.<span class="me1">out</span><span class="br0">)</span><span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
|
|
<span class="kw1">return</span> <span class="br0">{</span> std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>ret1.<span class="me1">in</span><span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>ret2.<span class="me1">in</span><span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>ret2.<span class="me1">out</span><span class="br0">)</span> <span class="br0">}</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
|
|
<span class="kw1">template</span><span class="sy1"><</span> ranges<span class="sy4">::</span><span class="me2">input_range</span> R1, ranges<span class="sy4">::</span><span class="me2">input_range</span> R2, std<span class="sy4">::</span><span class="me2">weakly_incrementable</span> O,
|
|
<span class="kw1">class</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span>,
|
|
<span class="kw1">class</span> Proj1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>, <span class="kw1">class</span> Proj2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span> <span class="sy1">></span>
|
|
requires std<span class="sy4">::</span><span class="me2">mergeable</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R1<span class="sy1">></span>, ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R2<span class="sy1">></span>,
|
|
O, Comp, Proj1, Proj2<span class="sy1">></span>
|
|
<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">merge_result</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R1<span class="sy1">></span>,
|
|
ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R2<span class="sy1">></span>, O<span class="sy1">></span>
|
|
operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span> R1<span class="sy3">&&</span> r1, R2<span class="sy3">&&</span> r2, O result, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>,
|
|
Proj1 proj1 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj2 proj2 <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
|
|
<span class="kw1">return</span> <span class="br0">(</span><span class="sy2">*</span>this<span class="br0">)</span><span class="br0">(</span>ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r1<span class="br0">)</span>, ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r1<span class="br0">)</span>,
|
|
ranges<span class="sy4">::</span><span class="me2">begin</span><span class="br0">(</span>r2<span class="br0">)</span>, ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r2<span class="br0">)</span>,
|
|
std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>result<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>comp<span class="br0">)</span>,
|
|
std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>proj1<span class="br0">)</span>, std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>proj2<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
<span class="br0">}</span><span class="sy4">;</span>
|
|
|
|
<span class="kw1">inline</span> <span class="kw4">constexpr</span> merge_fn merge<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></pre></div>
|
|
</div>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
|
|
<div class="t-example">
|
|
<div class="t-example-live-link"></div>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="cpp source-cpp">
|
|
<pre class="de1"><span class="co2">#include <algorithm></span>
|
|
<span class="co2">#include <iostream></span>
|
|
<span class="co2">#include <iterator></span>
|
|
<span class="co2">#include <vector></span>
|
|
|
|
<span class="kw4">void</span> print<span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span><span class="sy3">&</span> in1, <span class="kw4">const</span> <span class="kw4">auto</span><span class="sy3">&</span> in2, <span class="kw4">auto</span> first, <span class="kw4">auto</span> last<span class="br0">)</span> <span class="br0">{</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"{ "</span><span class="sy4">;</span>
|
|
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span><span class="sy3">&</span> e <span class="sy4">:</span> in1<span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> e <span class="sy1"><<</span> <span class="st0">' '</span><span class="sy4">;</span> <span class="br0">}</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"} +<span class="es1">\n</span>{ "</span><span class="sy4">;</span>
|
|
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span><span class="sy3">&</span> e <span class="sy4">:</span> in2<span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> e <span class="sy1"><<</span> <span class="st0">' '</span><span class="sy4">;</span> <span class="br0">}</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"} =<span class="es1">\n</span>{ "</span><span class="sy4">;</span>
|
|
<span class="kw1">while</span> <span class="br0">(</span><span class="sy3">!</span><span class="br0">(</span>first <span class="sy1">==</span> last<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="sy2">*</span>first<span class="sy2">++</span> <span class="sy1"><<</span> <span class="st0">' '</span><span class="sy4">;</span> <span class="br0">}</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"}<span class="es1">\n</span><span class="es1">\n</span>"</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
|
|
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
<a href="cpp-container-vector.html"><span class="kw1269">std::<span class="me2">vector</span></span></a><span class="sy1"><</span><span class="kw4">int</span><span class="sy1">></span> in1, in2, out<span class="sy4">;</span>
|
|
|
|
in1 <span class="sy1">=</span> <span class="br0">{</span><span class="nu0">1</span>, <span class="nu0">2</span>, <span class="nu0">3</span>, <span class="nu0">4</span>, <span class="nu0">5</span><span class="br0">}</span><span class="sy4">;</span>
|
|
in2 <span class="sy1">=</span> <span class="br0">{</span> <span class="nu0">3</span>, <span class="nu0">4</span>, <span class="nu0">5</span>, <span class="nu0">6</span>, <span class="nu0">7</span><span class="br0">}</span><span class="sy4">;</span>
|
|
out.<span class="me1">resize</span><span class="br0">(</span>in1.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy2">+</span> in2.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw4">const</span> <span class="kw4">auto</span> ret <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">merge</span><span class="br0">(</span>in1, in2, out.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
print<span class="br0">(</span>in1, in2, out.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, ret.<span class="me1">out</span><span class="br0">)</span><span class="sy4">;</span>
|
|
|
|
in1 <span class="sy1">=</span> <span class="br0">{</span><span class="nu0">1</span>, <span class="nu0">2</span>, <span class="nu0">3</span>, <span class="nu0">4</span>, <span class="nu0">5</span>, <span class="nu0">5</span>, <span class="nu0">5</span><span class="br0">}</span><span class="sy4">;</span>
|
|
in2 <span class="sy1">=</span> <span class="br0">{</span> <span class="nu0">3</span>, <span class="nu0">4</span>, <span class="nu0">5</span>, <span class="nu0">6</span>, <span class="nu0">7</span><span class="br0">}</span><span class="sy4">;</span>
|
|
out.<span class="me1">clear</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
|
|
out.<span class="me1">reserve</span><span class="br0">(</span>in1.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy2">+</span> in2.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">merge</span><span class="br0">(</span>in1, in2, <a href="cpp-iterator-back_inserter.html"><span class="kw665">std::<span class="me2">back_inserter</span></span></a><span class="br0">(</span>out<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
print<span class="br0">(</span>in1, in2, out.<span class="me1">cbegin</span><span class="br0">(</span><span class="br0">)</span>, out.<span class="me1">cend</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>输出：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">{ 1 2 3 4 5 } +
|
|
{ 3 4 5 6 7 } =
|
|
{ 1 2 3 3 4 4 5 5 6 7 }
|
|
|
|
{ 1 2 3 4 5 5 5 } +
|
|
{ 3 4 5 6 7 } =
|
|
{ 1 2 3 3 4 4 5 5 5 5 6 7 }</pre></div>
|
|
</div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-inplace_merge.html"><span class="t-lines"><span>ranges::inplace_merge</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>在原位归并两个有序范围<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-is_sorted.html"><span class="t-lines"><span>ranges::is_sorted</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>检查范围是否以升序排序<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-set_union.html"><span class="t-lines"><span>ranges::set_union</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>计算两个集合的并集<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-sort.html"><span class="t-lines"><span>ranges::sort</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>将范围按升序排序<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-stable_sort.html"><span class="t-lines"><span>ranges::stable_sort</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>将范围内的元素排序，同时保持相等的元素之间的顺序<br />
|
|
<span class="t-mark">(niebloid)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-merge.html"><span class="t-lines"><span>merge</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>归并两个已排序的范围<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|