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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::unordered_set&lt;Key,Hash,KeyEqual,Allocator&gt;::</span>merge</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-container.html">container</a>&lrm; | <a href="cpp-container-unordered_set.html">unordered set</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> H2, <span class="kw1">class</span> P2<span class="sy1">&gt;</span><br />
<span class="kw4">void</span> merge<span class="br0">(</span> <a href="cpp-container-unordered_set.html"><span class="kw1289">std::<span class="me2">unordered_set</span></span></a><span class="sy1">&lt;</span>Key, H2, P2, Allocator<span class="sy1">&gt;</span><span class="sy3">&amp;</span> source <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(1)</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> H2, <span class="kw1">class</span> P2<span class="sy1">&gt;</span><br />
<span class="kw4">void</span> merge<span class="br0">(</span> <a href="cpp-container-unordered_set.html"><span class="kw1289">std::<span class="me2">unordered_set</span></span></a><span class="sy1">&lt;</span>Key, H2, P2, Allocator<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span> source <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(2)</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> H2, <span class="kw1">class</span> P2<span class="sy1">&gt;</span><br />
<span class="kw4">void</span> merge<span class="br0">(</span> <a href="cpp-container-unordered_multiset.html"><span class="kw1291">std::<span class="me2">unordered_multiset</span></span></a><span class="sy1">&lt;</span>Key, H2, P2, Allocator<span class="sy1">&gt;</span><span class="sy3">&amp;</span> source <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(3)</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> H2, <span class="kw1">class</span> P2<span class="sy1">&gt;</span><br />
<span class="kw4">void</span> merge<span class="br0">(</span> <a href="cpp-container-unordered_multiset.html"><span class="kw1291">std::<span class="me2">unordered_multiset</span></span></a><span class="sy1">&lt;</span>Key, H2, P2, Allocator<span class="sy1">&gt;</span><span class="sy3">&amp;&amp;</span> source <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(4)</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
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<p>&#35797;&#22270;&#25552;&#21462;&#65288;&ldquo;&#25509;&#21512;&rdquo;&#65289; <code>source</code> &#20013;&#27599;&#20010;&#20803;&#32032;&#65292;&#24182;&#29992; <code>*this</code> &#30340;&#25955;&#21015;&#20989;&#25968;&#19982;&#38190;&#30456;&#31561;&#35859;&#35789;&#25554;&#20837;&#21040; <code>*this</code> &#12290; &#33509; <code>*this</code> &#20013;&#26377;&#20803;&#32032;&#65292;&#20854;&#38190;&#31561;&#20215;&#20110;&#26469;&#33258; <code>source</code> &#20013;&#20803;&#32032;&#30340;&#38190;&#65292;&#21017;&#19981;&#20174; <code>source</code> &#25552;&#21462;&#35813;&#20803;&#32032;&#12290; &#19981;&#22797;&#21046;&#25110;&#31227;&#21160;&#20803;&#32032;&#65292;&#21482;&#20250;&#37325;&#25351;&#21521;&#23481;&#22120;&#32467;&#28857;&#30340;&#20869;&#37096;&#25351;&#38024;&#12290;&#25351;&#21521;&#34987;&#36716;&#31227;&#20803;&#32032;&#30340;&#25152;&#26377;&#25351;&#38024;&#21644;&#24341;&#29992;&#20445;&#25345;&#21512;&#27861;&#65292;&#20294;&#29616;&#22312;&#25351;&#20195;&#21040; <code>*this</code> &#20013;&#32780;&#38750;&#21040; <code>source</code> &#20013;&#12290;&#25351;&#20195;&#34987;&#36716;&#31227;&#20803;&#32032;&#30340;&#36845;&#20195;&#22120;&#21644;&#25152;&#26377;&#25351;&#20195;&#21040; <code>*this</code> &#30340;&#36845;&#20195;&#22120;&#34987;&#38750;&#27861;&#21270;&#12290;&#25351;&#21521;&#30041;&#22312; <code>source</code> &#20013;&#20803;&#32032;&#30340;&#36845;&#20195;&#22120;&#20445;&#25345;&#21512;&#27861;&#12290;</p>
<p>&#33509; <span class="t-c"><span class="mw-geshi cpp source-cpp">get_allocator<span class="br0">(</span><span class="br0">)</span> <span class="sy3">!</span><span class="sy1">=</span> source.<span class="me1">get_allocator</span><span class="br0">(</span><span class="br0">)</span></span></span> &#21017;&#34892;&#20026;&#26410;&#23450;&#20041;&#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
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<td>source</td>
<td>-</td>
<td>&#20256;&#36882;&#32467;&#28857;&#26469;&#28304;&#30340;&#20860;&#23481;&#23481;&#22120;</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#65288;&#26080;&#65289;</p>
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<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">&#22797;&#26434;&#24230;</span></h3>
<p>&#24179;&#22343;&#24773;&#20917; O(N) &#65292;&#26368;&#22351;&#24773;&#20917; O(N*size()+N) &#65292;&#20854;&#20013; N &#20026; <code>source.size()</code> &#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;unordered_set&gt;</span>
<span class="co1">// &#25171;&#21360;&#20986;&#23481;&#22120;</span>
<span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Os, <span class="kw1">class</span> K<span class="sy1">&gt;</span>
Os<span class="sy3">&amp;</span> operator<span class="sy1">&lt;&lt;</span><span class="br0">(</span>Os<span class="sy3">&amp;</span> os, <span class="kw4">const</span> <a href="cpp-container-unordered_set.html"><span class="kw1289">std::<span class="me2">unordered_set</span></span></a><span class="sy1">&lt;</span>K<span class="sy1">&gt;</span><span class="sy3">&amp;</span> v<span class="br0">)</span> <span class="br0">{</span>
os <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;[&#39;</span> <span class="sy1">&lt;&lt;</span> v.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;] {&quot;</span><span class="sy4">;</span>
<span class="kw4">bool</span> o<span class="br0">{</span><span class="br0">}</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">&amp;</span> e <span class="sy4">:</span> v<span class="br0">)</span>
os <span class="sy1">&lt;&lt;</span> <span class="br0">(</span>o <span class="sy4">?</span> <span class="st0">&quot;, &quot;</span> <span class="sy4">:</span> <span class="br0">(</span>o <span class="sy1">=</span> <span class="nu0">1</span>, <span class="st0">&quot; &quot;</span><span class="br0">)</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> e<span class="sy4">;</span>
<span class="kw1">return</span> os <span class="sy1">&lt;&lt;</span> <span class="st0">&quot; }<span class="es1">\n</span>&quot;</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-unordered_set.html"><span class="kw1289">std::<span class="me2">unordered_set</span></span></a><span class="sy1">&lt;</span><span class="kw4">char</span><span class="sy1">&gt;</span>
p<span class="br0">{</span> <span class="st0">&#39;C&#39;</span>, <span class="st0">&#39;B&#39;</span>, <span class="st0">&#39;B&#39;</span>, <span class="st0">&#39;A&#39;</span> <span class="br0">}</span>,
q<span class="br0">{</span> <span class="st0">&#39;E&#39;</span>, <span class="st0">&#39;D&#39;</span>, <span class="st0">&#39;E&#39;</span>, <span class="st0">&#39;C&#39;</span> <span class="br0">}</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;p: &quot;</span> <span class="sy1">&lt;&lt;</span> p <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;q: &quot;</span> <span class="sy1">&lt;&lt;</span> q<span class="sy4">;</span>
p.<span class="me1">merge</span><span class="br0">(</span>q<span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;p.merge(q);<span class="es1">\n</span>&quot;</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;p: &quot;</span> <span class="sy1">&lt;&lt;</span> p <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;q: &quot;</span> <span class="sy1">&lt;&lt;</span> q<span class="sy4">;</span>
<span class="br0">}</span></pre></div>
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<p>&#21487;&#33021;&#30340;&#36755;&#20986;&#65306;</p>
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<pre class="de1">p: [3] { A, B, C }
q: [3] { C, D, E }
p.merge(q);
p: [5] { E, D, A, B, C }
q: [1] { C }</pre></div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="cpp-container-unordered_set-extract.html"><span class="t-lines"><span>extract</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div>
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<td>&#20174;&#21478;&#19968;&#23481;&#22120;&#37322;&#20986;&#32467;&#28857;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div class="t-dsc-member-div">
<div><a href="cpp-container-unordered_set-insert.html"><span class="t-lines"><span>insert</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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<td>&#25554;&#20837;&#20803;&#32032;<span class="t-rev-inl t-since-cxx17"><span>&#25110;&#32467;&#28857;</span> <span><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></span></span><br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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