deploy: 72ab1fd

Author: yanglbme

en/lc/346/index.html

@@ -16035,9 +16035,9 @@
       <ul class="md-nav__list">
 
           <li class="md-nav__item">
-  <a href="#solution-1" class="md-nav__link">
+  <a href="#solution-1-counting" class="md-nav__link">
     <span class="md-ellipsis">
-      Solution 1
+      Solution 1: Counting
     </span>
   </a>
 
@@ -87172,7 +87172,10 @@ <h2 id="description">Description</h2>
 <h2 id="solutions">Solutions</h2>
 <!-- solution:start -->
 
-<h3 id="solution-1">Solution 1</h3>
+<h3 id="solution-1-counting">Solution 1: Counting</h3>
+<p>We use a hash table or an array of length <span class="arithmatex">\(26\)</span> <span class="arithmatex">\(\text{cnt}\)</span> to store the frequency of each character. Then, we traverse each character <span class="arithmatex">\(\text{s[i]}\)</span> from the beginning. If <span class="arithmatex">\(\text{cnt[s[i]]}\)</span> is <span class="arithmatex">\(1\)</span>, we return <span class="arithmatex">\(i\)</span>.</p>
+<p>If no such character is found after the traversal, we return <span class="arithmatex">\(-1\)</span>.</p>
+<p>The time complexity is <span class="arithmatex">\(O(n)\)</span>, where <span class="arithmatex">\(n\)</span> is the length of the string. The space complexity is <span class="arithmatex">\(O(|\Sigma|)\)</span>, where <span class="arithmatex">\(\Sigma\)</span> is the character set. In this problem, the character set consists of lowercase letters, so <span class="arithmatex">\(|\Sigma|=26\)</span>.</p>
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@@ -87296,12 +87299,12 @@ <h3 id="solution-1">Solution 1</h3>
 <span class="normal">10</span>
 <span class="normal">11</span>
 <span class="normal">12</span></pre></div></td><td class="code"><div><pre><span></span><code><span class="kd">function</span><span class="w"> </span><span class="nx">firstUniqChar</span><span class="p">(</span><span class="nx">s</span><span class="o">:</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="o">:</span><span class="w"> </span><span class="kt">number</span><span class="w"> </span><span class="p">{</span>
-<span class="w">    </span><span class="kd">const</span><span class="w"> </span><span class="nx">cnt</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="ow">new</span><span class="w"> </span><span class="nb">Array</span><span class="p">(</span><span class="mf">26</span><span class="p">).</span><span class="nx">fill</span><span class="p">(</span><span class="mf">0</span><span class="p">);</span>
+<span class="w">    </span><span class="kd">const</span><span class="w"> </span><span class="nx">cnt</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="ow">new</span><span class="w"> </span><span class="nb">Map</span><span class="o">&lt;</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">number</span><span class="o">&gt;</span><span class="p">();</span>
 <span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">const</span><span class="w"> </span><span class="nx">c</span><span class="w"> </span><span class="k">of</span><span class="w"> </span><span class="nx">s</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
-<span class="w">        </span><span class="nx">cnt</span><span class="p">[</span><span class="nx">c</span><span class="p">.</span><span class="nx">charCodeAt</span><span class="p">(</span><span class="mf">0</span><span class="p">)</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mf">97</span><span class="p">]</span><span class="o">++</span><span class="p">;</span>
+<span class="w">        </span><span class="nx">cnt</span><span class="p">.</span><span class="nx">set</span><span class="p">(</span><span class="nx">c</span><span class="p">,</span><span class="w"> </span><span class="p">(</span><span class="nx">cnt</span><span class="p">.</span><span class="nx">get</span><span class="p">(</span><span class="nx">c</span><span class="p">)</span><span class="w"> </span><span class="o">||</span><span class="w"> </span><span class="mf">0</span><span class="p">)</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mf">1</span><span class="p">);</span>
 <span class="w">    </span><span class="p">}</span>
-<span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mf">0</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">s</span><span class="p">.</span><span class="nx">length</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
-<span class="w">        </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nx">cnt</span><span class="p">[</span><span class="nx">s</span><span class="p">.</span><span class="nx">charCodeAt</span><span class="p">(</span><span class="nx">i</span><span class="p">)</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mf">97</span><span class="p">]</span><span class="w"> </span><span class="o">===</span><span class="w"> </span><span class="mf">1</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
+<span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mf">0</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">s</span><span class="p">.</span><span class="nx">length</span><span class="p">;</span><span class="w"> </span><span class="o">++</span><span class="nx">i</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
+<span class="w">        </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nx">cnt</span><span class="p">.</span><span class="nx">get</span><span class="p">(</span><span class="nx">s</span><span class="p">[</span><span class="nx">i</span><span class="p">])</span><span class="w"> </span><span class="o">===</span><span class="w"> </span><span class="mf">1</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="k">return</span><span class="w"> </span><span class="nx">i</span><span class="p">;</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span>
@@ -87330,12 +87333,12 @@ <h3 id="solution-1">Solution 1</h3>
 <span class="cm"> * @return {number}</span>
 <span class="cm"> */</span>
 <span class="kd">var</span><span class="w"> </span><span class="nx">firstUniqChar</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kd">function</span><span class="w"> </span><span class="p">(</span><span class="nx">s</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
-<span class="w">    </span><span class="kd">const</span><span class="w"> </span><span class="nx">cnt</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="ow">new</span><span class="w"> </span><span class="nb">Array</span><span class="p">(</span><span class="mf">26</span><span class="p">).</span><span class="nx">fill</span><span class="p">(</span><span class="mf">0</span><span class="p">);</span>
+<span class="w">    </span><span class="kd">const</span><span class="w"> </span><span class="nx">cnt</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="ow">new</span><span class="w"> </span><span class="nb">Map</span><span class="p">();</span>
 <span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">const</span><span class="w"> </span><span class="nx">c</span><span class="w"> </span><span class="k">of</span><span class="w"> </span><span class="nx">s</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
-<span class="w">        </span><span class="o">++</span><span class="nx">cnt</span><span class="p">[</span><span class="nx">c</span><span class="p">.</span><span class="nx">charCodeAt</span><span class="p">()</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="s1">&#39;a&#39;</span><span class="p">.</span><span class="nx">charCodeAt</span><span class="p">()];</span>
+<span class="w">        </span><span class="nx">cnt</span><span class="p">.</span><span class="nx">set</span><span class="p">(</span><span class="nx">c</span><span class="p">,</span><span class="w"> </span><span class="p">(</span><span class="nx">cnt</span><span class="p">.</span><span class="nx">get</span><span class="p">(</span><span class="nx">c</span><span class="p">)</span><span class="w"> </span><span class="o">||</span><span class="w"> </span><span class="mf">0</span><span class="p">)</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mf">1</span><span class="p">);</span>
 <span class="w">    </span><span class="p">}</span>
 <span class="w">    </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kd">let</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mf">0</span><span class="p">;</span><span class="w"> </span><span class="nx">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="nx">s</span><span class="p">.</span><span class="nx">length</span><span class="p">;</span><span class="w"> </span><span class="o">++</span><span class="nx">i</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
-<span class="w">        </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nx">cnt</span><span class="p">[</span><span class="nx">s</span><span class="p">[</span><span class="nx">i</span><span class="p">].</span><span class="nx">charCodeAt</span><span class="p">()</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="s1">&#39;a&#39;</span><span class="p">.</span><span class="nx">charCodeAt</span><span class="p">()]</span><span class="w"> </span><span class="o">===</span><span class="w"> </span><span class="mf">1</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
+<span class="w">        </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="nx">cnt</span><span class="p">.</span><span class="nx">get</span><span class="p">(</span><span class="nx">s</span><span class="p">[</span><span class="nx">i</span><span class="p">])</span><span class="w"> </span><span class="o">===</span><span class="w"> </span><span class="mf">1</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
 <span class="w">            </span><span class="k">return</span><span class="w"> </span><span class="nx">i</span><span class="p">;</span>
 <span class="w">        </span><span class="p">}</span>
 <span class="w">    </span><span class="p">}</span>
@@ -87412,6 +87415,11 @@ <h3 id="solution-1">Solution 1</h3>
 
     <nav>
 
+        <a href="https://github.com/acbin" class="md-author" title="@acbin">
+          
+          <img src="https://avatars.githubusercontent.com/u/44314231?v=4&size=72" alt="acbin">
+        </a>
+      
         <a href="https://github.com/yanglbme" class="md-author" title="@yanglbme">
 
           <img src="https://avatars.githubusercontent.com/u/21008209?v=4&size=72" alt="yanglbme">