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    <h2 class="fw-bold">14425번 - 문자열 집합</h2>
<h4 id="-">분류 : 자료 구조, 문자열</h4>
<h4 id="-">문제</h4>
<p>총 N개의 문자열로 이루어진 집합 S가 주어진다.</p>
<p>입력으로 주어지는 M개의 문자열 중에서 집합 S에 포함되어 있는 것이 총 몇 개인지 구하는 프로그램을 작성하시오.</p>
<h4 id="-">풀이</h4>
<p>맵을 이용하면 간단히 풀 수 있는 문제이다.</p>
<p>맵의 경우 key에 대한 탐색이 O(1) 이기 때문에 시간초과가 나지 않지만</p>
<p>문자열 집합을 리스트에 저장할 경우 O(n)으로 시간 초과가 발생하게 된다.</p>
<div class="sourceCode" id="cb1"><pre
class="sourceCode java"><code class="sourceCode java"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="kw">import</span> <span class="im">java</span><span class="op">.</span><span class="im">io</span><span class="op">.</span><span class="im">BufferedReader</span><span class="op">;</span></span>
<span id="cb1-2"><a href="#cb1-2" aria-hidden="true" tabindex="-1"></a><span class="kw">import</span> <span class="im">java</span><span class="op">.</span><span class="im">io</span><span class="op">.</span><span class="im">IOException</span><span class="op">;</span></span>
<span id="cb1-3"><a href="#cb1-3" aria-hidden="true" tabindex="-1"></a><span class="kw">import</span> <span class="im">java</span><span class="op">.</span><span class="im">io</span><span class="op">.</span><span class="im">InputStreamReader</span><span class="op">;</span></span>
<span id="cb1-4"><a href="#cb1-4" aria-hidden="true" tabindex="-1"></a><span class="kw">import</span> <span class="im">java</span><span class="op">.</span><span class="im">util</span><span class="op">.</span><span class="im">HashMap</span><span class="op">;</span></span>
<span id="cb1-5"><a href="#cb1-5" aria-hidden="true" tabindex="-1"></a><span class="kw">import</span> <span class="im">java</span><span class="op">.</span><span class="im">util</span><span class="op">.</span><span class="im">Map</span><span class="op">;</span></span>
<span id="cb1-6"><a href="#cb1-6" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-7"><a href="#cb1-7" aria-hidden="true" tabindex="-1"></a><span class="kw">public</span> <span class="kw">class</span> Main <span class="op">{</span></span>
<span id="cb1-8"><a href="#cb1-8" aria-hidden="true" tabindex="-1"></a>    <span class="dt">static</span> <span class="dt">int</span> n<span class="op">,</span>m<span class="op">;</span></span>
<span id="cb1-9"><a href="#cb1-9" aria-hidden="true" tabindex="-1"></a>    <span class="dt">static</span> <span class="bu">Map</span><span class="op">&lt;</span><span class="bu">String</span><span class="op">,</span><span class="bu">Boolean</span><span class="op">&gt;</span> stringMap <span class="op">=</span> <span class="kw">new</span> <span class="bu">HashMap</span><span class="op">&lt;&gt;();</span></span>
<span id="cb1-10"><a href="#cb1-10" aria-hidden="true" tabindex="-1"></a>    <span class="kw">public</span> <span class="dt">static</span> <span class="dt">void</span> <span class="fu">main</span><span class="op">(</span><span class="bu">String</span><span class="op">[]</span> args<span class="op">)</span> <span class="kw">throws</span> <span class="bu">IOException</span> <span class="op">{</span></span>
<span id="cb1-11"><a href="#cb1-11" aria-hidden="true" tabindex="-1"></a>        <span class="bu">BufferedReader</span> br <span class="op">=</span> <span class="kw">new</span> <span class="bu">BufferedReader</span><span class="op">(</span><span class="kw">new</span> <span class="bu">InputStreamReader</span><span class="op">(</span><span class="bu">System</span><span class="op">.</span><span class="fu">in</span><span class="op">));</span></span>
<span id="cb1-12"><a href="#cb1-12" aria-hidden="true" tabindex="-1"></a>        <span class="bu">String</span><span class="op">[]</span> inputTmp <span class="op">=</span> br<span class="op">.</span><span class="fu">readLine</span><span class="op">().</span><span class="fu">split</span><span class="op">(</span><span class="st">&quot; &quot;</span><span class="op">);</span></span>
<span id="cb1-13"><a href="#cb1-13" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-14"><a href="#cb1-14" aria-hidden="true" tabindex="-1"></a>        n <span class="op">=</span> <span class="bu">Integer</span><span class="op">.</span><span class="fu">parseInt</span><span class="op">(</span>inputTmp<span class="op">[</span><span class="dv">0</span><span class="op">]);</span></span>
<span id="cb1-15"><a href="#cb1-15" aria-hidden="true" tabindex="-1"></a>        m <span class="op">=</span> <span class="bu">Integer</span><span class="op">.</span><span class="fu">parseInt</span><span class="op">(</span>inputTmp<span class="op">[</span><span class="dv">1</span><span class="op">]);</span></span>
<span id="cb1-16"><a href="#cb1-16" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-17"><a href="#cb1-17" aria-hidden="true" tabindex="-1"></a>        <span class="dt">int</span> res <span class="op">=</span> <span class="dv">0</span><span class="op">;</span></span>
<span id="cb1-18"><a href="#cb1-18" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-19"><a href="#cb1-19" aria-hidden="true" tabindex="-1"></a>        <span class="cf">for</span> <span class="op">(</span><span class="dt">int</span> i <span class="op">=</span> <span class="dv">0</span><span class="op">;</span> i <span class="op">&lt;</span> n<span class="op">;</span> i<span class="op">++)</span></span>
<span id="cb1-20"><a href="#cb1-20" aria-hidden="true" tabindex="-1"></a>            stringMap<span class="op">.</span><span class="fu">put</span><span class="op">(</span>br<span class="op">.</span><span class="fu">readLine</span><span class="op">().</span><span class="fu">strip</span><span class="op">(),</span><span class="kw">true</span><span class="op">);</span></span>
<span id="cb1-21"><a href="#cb1-21" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-22"><a href="#cb1-22" aria-hidden="true" tabindex="-1"></a>        <span class="cf">for</span> <span class="op">(</span><span class="dt">int</span> i <span class="op">=</span> <span class="dv">0</span><span class="op">;</span> i <span class="op">&lt;</span> m<span class="op">;</span> i<span class="op">++)</span></span>
<span id="cb1-23"><a href="#cb1-23" aria-hidden="true" tabindex="-1"></a>            <span class="cf">if</span> <span class="op">(</span><span class="fu">isInclude</span><span class="op">(</span>br<span class="op">.</span><span class="fu">readLine</span><span class="op">().</span><span class="fu">strip</span><span class="op">()))</span></span>
<span id="cb1-24"><a href="#cb1-24" aria-hidden="true" tabindex="-1"></a>                res<span class="op">++;</span></span>
<span id="cb1-25"><a href="#cb1-25" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-26"><a href="#cb1-26" aria-hidden="true" tabindex="-1"></a>        <span class="bu">System</span><span class="op">.</span><span class="fu">out</span><span class="op">.</span><span class="fu">println</span><span class="op">(</span>res<span class="op">);</span></span>
<span id="cb1-27"><a href="#cb1-27" aria-hidden="true" tabindex="-1"></a>    <span class="op">}</span></span>
<span id="cb1-28"><a href="#cb1-28" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-29"><a href="#cb1-29" aria-hidden="true" tabindex="-1"></a>    <span class="dt">static</span> <span class="dt">boolean</span> <span class="fu">isInclude</span><span class="op">(</span><span class="bu">String</span> s<span class="op">)</span> <span class="op">{</span></span>
<span id="cb1-30"><a href="#cb1-30" aria-hidden="true" tabindex="-1"></a>        <span class="cf">return</span> stringMap<span class="op">.</span><span class="fu">containsKey</span><span class="op">(</span>s<span class="op">);</span></span>
<span id="cb1-31"><a href="#cb1-31" aria-hidden="true" tabindex="-1"></a>    <span class="op">}</span></span>
<span id="cb1-32"><a href="#cb1-32" aria-hidden="true" tabindex="-1"></a><span class="op">}</span></span></code></pre></div>


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