304 lines
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304 lines
34 KiB
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<title>std::ranges::next_permutation, std::ranges::next_permutation_result</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_algorithm_ranges_next_permutation skin-cppreference2 action-view cpp-navbar">
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ranges::</span>next_permutation, <span style="font-size:0.7em; line-height:130%">std::ranges::</span>next_permutation_result</h1>
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<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>
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<div>定义于头文件 <code><a href="cpp-header-algorithm.html"><algorithm></a></code></div>
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<div>调用签名</div>
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<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">bidirectional_iterator</span> I, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I<span class="sy1">></span> S,<br /></span>
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<p> <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> Proj <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span><span class="sy1">></span><br />
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requires std<span class="sy4">::</span><span class="me2">sortable</span><span class="sy1"><</span>I, Comp, Proj<span class="sy1">></span><br />
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>I<span class="sy1">></span><br /></p>
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next_permutation<span class="br0">(</span>I first, S last, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj proj <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span><span class="br0">)</span><span class="sy4">;</span></div>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<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">bidirectional_range</span> R, <span class="kw1">class</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span>,<br /></span>
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<p> <span class="kw1">class</span> Proj <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span><span class="sy1">></span><br />
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requires std<span class="sy4">::</span><span class="me2">sortable</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R<span class="sy1">></span>, Comp, Proj<span class="sy1">></span><br />
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R<span class="sy1">>></span><br /></p>
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next_permutation<span class="br0">(</span>R<span class="sy3">&&</span> r, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj proj <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span><span class="br0">)</span><span class="sy4">;</span></div>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<div>辅助类型</div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> I<span class="sy1">></span><br />
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<span class="kw1">using</span> next_permutation_result <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">in_found_result</span><span class="sy1"><</span>I<span class="sy1">></span><span class="sy4">;</span></span></div>
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<td>(3)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<div class="t-li1"><span class="t-li">1)</span> 将范围 <code>[first, last)</code> 变换到下个<i>排列</i>，其中所有排列的集合<i>词法上</i>相对于比较函数对象 <code>comp</code> 和投影函数对象 <code>proj</code> 定序。若存在<i>“下个排列”</i>则返回 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">{</span>last, <span class="kw2">true</span><span class="br0">}</span></span></span> ；否则将范围变换到词法上的首个排列，如同用 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">sort</span><span class="br0">(</span>first, last, comp, proj<span class="br0">)</span></span></span> ，并返回 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">{</span>last, <span class="kw2">false</span><span class="br0">}</span></span></span> 。</div>
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<div class="t-li1"><span class="t-li">2)</span> 同 <span class="t-v">(1)</span> ，但以 <code>r</code> 为源范围，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>r<span class="br0">)</span></span></span> 为 <code>first</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>r<span class="br0">)</span></span></span> 为 <code>last</code> 。</div>
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<p>此页面上描述的仿函数实体是 <i>niebloid</i> ，即：</p>
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<ul>
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<li>调用它们中的任何一者时不可指定显式模板实参。</li>
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<li>它们无一对<a href="cpp-language-adl.html">实参依赖查找</a>可见。</li>
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<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>
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</ul>
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<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>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
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<table class="t-par-begin">
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<td>first, last</td>
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<td>-</td>
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<td>要<i>重排</i>的元素范围</td>
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<tr class="t-par">
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<td>r</td>
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<td>-</td>
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<td>要<i>重排</i>的元素范围</td>
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<td>comp</td>
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<td>-</td>
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<td>若第一参数<i>小于</i>第二个则返回 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> 的比较函数对象</td>
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<td>proj</td>
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<td>-</td>
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<td>应用到元素的投影</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<div class="t-li1"><span class="t-li">1)</span> 若新排列词法上<i>大于</i>旧者则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>I<span class="sy1">></span><span class="br0">{</span>last, <span class="kw2">true</span><span class="br0">}</span></span></span> 。若抵达最后的排列并重置范围为首排列则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>I<span class="sy1">></span><span class="br0">{</span>last, <span class="kw2">false</span><span class="br0">}</span></span></span> 。</div>
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<div class="t-li1"><span class="t-li">2)</span> 同 <span class="t-v">(1)</span> ，除了返回类型为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R<span class="sy1">>></span></span></span> 。</div>
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<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">异常</span></h3>
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<p>任何从迭代器操作或元素交换抛出的异常。</p>
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<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">复杂度</span></h3>
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<p>至多交换 <span class="mjax" style="display:none">\(\scriptsize N/2\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">N/2</span> 次，其中 <span class="mjax" style="display:none">\(\scriptsize N\)</span><span class="mjax-fallback texhtml" style="white-space: nowrap;">N</span> 在情况 <span class="t-v">(1)</span> 中为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>first, last<span class="br0">)</span></span></span> ，在情况 <span class="t-v">(2)</span> 中为 <span class="t-c"><span class="mw-geshi cpp source-cpp">ranges<span class="sy4">::</span><span class="me2">distance</span><span class="br0">(</span>r<span class="br0">)</span></span></span> 。在整个重排序列中，典型实现平均每次调用使用 3 次比较和 1.5 次交换。</p>
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<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">注解</span></h3>
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<p>实现（例如 <a rel="nofollow" class="external text" href="https://github.com/microsoft/STL/blob/main/stl/src/vector_algorithms.cpp">MSVC STL</a> ）可能在迭代器类型实现 <a href="cpp-iterator-contiguous_iterator.html"><code>contiguous_iterator</code></a> ，并且交换其值类型不调用非平凡的特殊成员函数或 <a href="cpp-language-adl.html">ADL</a> 所找到的 <code>swap</code> 时启用向量化。</p>
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<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>
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<table class="eq-fun-cpp-table">
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="kw1">struct</span> next_permutation_fn <span class="br0">{</span>
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<span class="kw1">template</span><span class="sy1"><</span>std<span class="sy4">::</span><span class="me2">bidirectional_iterator</span> I, std<span class="sy4">::</span><span class="me2">sentinel_for</span><span class="sy1"><</span>I<span class="sy1">></span> S,
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<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> Proj <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span><span class="sy1">></span>
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requires std<span class="sy4">::</span><span class="me2">sortable</span><span class="sy1"><</span>I, Comp, Proj<span class="sy1">></span>
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>I<span class="sy1">></span>
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operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span>I first, S last, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj proj <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>
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<span class="co1">// 检查序列是否拥有至少二个元素</span>
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<span class="kw1">if</span> <span class="br0">(</span>first <span class="sy1">==</span> last<span class="br0">)</span>
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<span class="kw1">return</span> <span class="br0">{</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>first<span class="br0">)</span>, <span class="kw2">false</span><span class="br0">}</span><span class="sy4">;</span>
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I i_last <span class="br0">{</span>ranges<span class="sy4">::</span><span class="me2">next</span><span class="br0">(</span>first, last<span class="br0">)</span><span class="br0">}</span><span class="sy4">;</span>
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I i <span class="br0">{</span>i_last<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">if</span> <span class="br0">(</span>first <span class="sy1">==</span> <span class="sy2">--</span>i<span class="br0">)</span>
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<span class="kw1">return</span> <span class="br0">{</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>i_last<span class="br0">)</span>, <span class="kw2">false</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="co1">// 主“重排”循环</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="sy4">;;</span><span class="br0">)</span> <span class="br0">{</span>
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I i1 <span class="br0">{</span>i<span class="br0">}</span><span class="sy4">;</span>
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<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>proj, <span class="sy2">*--</span>i<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>proj, <span class="sy2">*</span>i1<span class="br0">)</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
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I j <span class="br0">{</span>i_last<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">while</span> <span class="br0">(</span><span class="sy3">!</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>proj, <span class="sy2">*</span>i<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>proj, <span class="sy2">*--</span>j<span class="br0">)</span><span class="br0">)</span><span class="br0">)</span>
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<span class="br0">{</span> <span class="br0">}</span>
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<a href="cpp-algorithm-iter_swap.html"><span class="kw1601">std::<span class="me2">iter_swap</span></span></a><span class="br0">(</span>i, j<span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-algorithm-reverse.html"><span class="kw1602">std::<span class="me2">reverse</span></span></a><span class="br0">(</span>i1, i_last<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">return</span> <span class="br0">{</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>i_last<span class="br0">)</span>, <span class="kw2">true</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="co1">// 耗尽重排“空格”</span>
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<span class="kw1">if</span> <span class="br0">(</span>i <span class="sy1">==</span> first<span class="br0">)</span> <span class="br0">{</span>
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<a href="cpp-algorithm-reverse.html"><span class="kw1602">std::<span class="me2">reverse</span></span></a><span class="br0">(</span>first, i_last<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">return</span> <span class="br0">{</span>std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>i_last<span class="br0">)</span>, <span class="kw2">false</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span>
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<span class="br0">}</span>
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<span class="kw1">template</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">bidirectional_range</span> R, <span class="kw1">class</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span>,
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<span class="kw1">class</span> Proj <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span><span class="sy1">></span>
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requires std<span class="sy4">::</span><span class="me2">sortable</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">iterator_t</span><span class="sy1"><</span>R<span class="sy1">></span>, Comp, Proj<span class="sy1">></span>
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<span class="kw4">constexpr</span> ranges<span class="sy4">::</span><span class="me2">next_permutation_result</span><span class="sy1"><</span>ranges<span class="sy4">::</span><span class="me2">borrowed_iterator_t</span><span class="sy1"><</span>R<span class="sy1">>></span>
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operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span>R<span class="sy3">&&</span> r, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj proj <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>
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<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>r<span class="br0">)</span>, ranges<span class="sy4">::</span><span class="me2">end</span><span class="br0">(</span>r<span class="br0">)</span>,
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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>proj<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">inline</span> <span class="kw4">constexpr</span> next_permutation_fn next_permutation<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span></pre></div>
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</div>
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</td>
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</tr>
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</table>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
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<div class="t-example">
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<div class="t-example-live-link"></div>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="co2">#include <algorithm></span>
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<span class="co2">#include <array></span>
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<span class="co2">#include <compare></span>
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<span class="co2">#include <functional></span>
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<span class="co2">#include <iostream></span>
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<span class="co2">#include <string></span>
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<span class="kw1">struct</span> S <span class="br0">{</span>
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<span class="kw4">char</span> c<span class="sy4">;</span>
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<span class="kw4">int</span> i<span class="sy4">;</span>
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<span class="kw4">auto</span> operator<span class="sy1"><=></span><span class="br0">(</span><span class="kw4">const</span> S<span class="sy3">&</span><span class="br0">)</span> <span class="kw4">const</span> <span class="sy1">=</span> <span class="kw1">default</span><span class="sy4">;</span>
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<span class="kw1">friend</span> <a href="cpp-io-basic_ostream.html"><span class="kw1729">std::<span class="me2">ostream</span></span></a><span class="sy3">&</span> operator<span class="sy1"><<</span> <span class="br0">(</span><a href="cpp-io-basic_ostream.html"><span class="kw1729">std::<span class="me2">ostream</span></span></a><span class="sy3">&</span> os, <span class="kw4">const</span> S<span class="sy3">&</span> s<span class="br0">)</span> <span class="br0">{</span>
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<span class="kw1">return</span> os <span class="sy1"><<</span> <span class="st0">"{'"</span> <span class="sy1"><<</span> s.<span class="me1">c</span> <span class="sy1"><<</span> <span class="st0">"', "</span> <span class="sy1"><<</span> s.<span class="me1">i</span> <span class="sy1"><<</span> <span class="st0">"}"</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw4">auto</span> print <span class="sy1">=</span> <span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">auto</span> <span class="kw4">const</span><span class="sy3">&</span> v, <span class="kw4">char</span> term <span class="sy1">=</span> <span class="st0">' '</span><span class="br0">)</span> <span class="br0">{</span>
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<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>
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<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> v<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>
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<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="sy1"><<</span> term<span class="sy4">;</span>
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<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
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<span class="br0">{</span>
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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"Generate all permutations (iterators case):<span class="es1">\n</span>"</span><span class="sy4">;</span>
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<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> s<span class="br0">{</span><span class="st0">"abc"</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">do</span> <span class="br0">{</span> print<span class="br0">(</span>s<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="kw1">while</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">next_permutation</span><span class="br0">(</span>s.<span class="me1">begin</span><span class="br0">(</span><span class="br0">)</span>, s.<span class="me1">end</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span>.<span class="me1">found</span><span class="br0">)</span><span class="sy4">;</span>
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<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="st0">"Generate all permutations (range case):<span class="es1">\n</span>"</span><span class="sy4">;</span>
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<a href="cpp-container-array.html"><span class="kw1268">std::<span class="me2">array</span></span></a> a<span class="br0">{</span><span class="st0">'a'</span>, <span class="st0">'b'</span>, <span class="st0">'c'</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">do</span> <span class="br0">{</span> print<span class="br0">(</span>a<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="kw1">while</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">next_permutation</span><span class="br0">(</span>a<span class="br0">)</span>.<span class="me1">found</span><span class="br0">)</span><span class="sy4">;</span>
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<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="st0">"Generate all permutations using comparator:<span class="es1">\n</span>"</span><span class="sy4">;</span>
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|
<span class="kw1">using</span> <span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">literals</span><span class="sy4">;</span>
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<a href="cpp-container-array.html"><span class="kw1268">std::<span class="me2">array</span></span></a> z<span class="br0">{</span> <span class="st0">"█"</span>s, <span class="st0">"▄"</span>s, <span class="st0">"▁"</span>s <span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">do</span> <span class="br0">{</span> print<span class="br0">(</span>z<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="kw1">while</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">next_permutation</span><span class="br0">(</span>z, <a href="cpp-utility-functional-greater.html"><span class="kw1037">std::<span class="me2">greater</span></span></a><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span>.<span class="me1">found</span><span class="br0">)</span><span class="sy4">;</span>
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<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="st0">"Generate all permutations using projection:<span class="es1">\n</span>"</span><span class="sy4">;</span>
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<a href="cpp-container-array.html"><span class="kw1268">std::<span class="me2">array</span></span></a><span class="sy1"><</span>S, <span class="nu0">3</span><span class="sy1">></span> r<span class="br0">{</span> S<span class="br0">{</span><span class="st0">'A'</span>,<span class="nu0">3</span><span class="br0">}</span>, S<span class="br0">{</span><span class="st0">'B'</span>,<span class="nu0">2</span><span class="br0">}</span>, S<span class="br0">{</span><span class="st0">'C'</span>,<span class="nu0">1</span><span class="br0">}</span> <span class="br0">}</span><span class="sy4">;</span>
|
|
<span class="kw1">do</span> <span class="br0">{</span> print<span class="br0">(</span>r, <span class="st0">'<span class="es1">\n</span>'</span><span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span>
|
|
<span class="kw1">while</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">next_permutation</span><span class="br0">(</span>r, <span class="br0">{</span><span class="br0">}</span>, <span class="sy3">&</span>S<span class="sy4">::</span><span class="me2">c</span><span class="br0">)</span>.<span class="me1">found</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">Generate all permutations (iterators case):
|
|
{ a b c } { a c b } { b a c } { b c a } { c a b } { c b a }
|
|
Generate all permutations (range case):
|
|
{ a b c } { a c b } { b a c } { b c a } { c a b } { c b a }
|
|
Generate all permutations using comparator:
|
|
{ █ ▄ ▁ } { █ ▁ ▄ } { ▄ █ ▁ } { ▄ ▁ █ } { ▁ █ ▄ } { ▁ ▄ █ }
|
|
Generate all permutations using projection:
|
|
{ {'A', 3} {'B', 2} {'C', 1} }
|
|
{ {'A', 3} {'C', 1} {'B', 2} }
|
|
{ {'B', 2} {'A', 3} {'C', 1} }
|
|
{ {'B', 2} {'C', 1} {'A', 3} }
|
|
{ {'C', 1} {'A', 3} {'B', 2} }
|
|
{ {'C', 1} {'B', 2} {'A', 3} }</pre></div>
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</div>
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</div>
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|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
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<table class="t-dsc-begin">
|
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<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-ranges-prev_permutation.html"><span class="t-lines"><span>ranges::prev_permutation</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>产生某个元素范围的按字典序下一个较小的排列<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_permutation.html"><span class="t-lines"><span>ranges::is_permutation</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>确定一个序列是否为另一序列的重排<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-next_permutation.html"><span class="t-lines"><span>next_permutation</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>产生某个元素范围的按字典顺序的下一个较大的排列<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-prev_permutation.html"><span class="t-lines"><span>prev_permutation</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>产生某个元素范围的按字典顺序的下一个较小的排列<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-algorithm-is_permutation.html"><span class="t-lines"><span>is_permutation</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>判断一个序列是否为另一个序列的排列<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
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<div class="visualClear"></div>
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</div>
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</div>
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</div>
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</body>
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</html>
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