Site updated: 2020-02-25 23:26:49
This commit is contained in:
Jimmy Xiang
@@ -95,6 +95,19 @@
|
||||
<div class="wrapper index-wrapper">
|
||||
<ul class="container list-container">
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-lcci0101/" class="wrapper post-i-link" title="LCCI 01.01.判定字符是否唯一">
|
||||
<div class="wrapper cover">
|
||||
<img src="/images/leetcode-0101.png" alt="LCCI 01.01.判定字符是否唯一">
|
||||
</div>
|
||||
<h3 class="wrapper title" title="LCCI 01.01.判定字符是否唯一">LCCI 01.01.判定字符是否唯一</h3>
|
||||
<p class="wrapper subtitle">
|
||||
LeetCode刷题计划
|
||||
</p>
|
||||
<div class="wrapper time">2020-02-25</div>
|
||||
</a>
|
||||
</li>
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-0000/" class="wrapper post-i-link" title="0000.为什么需要复杂度分析">
|
||||
<div class="wrapper cover">
|
||||
|
||||
@@ -95,6 +95,19 @@
|
||||
<div class="wrapper index-wrapper">
|
||||
<ul class="container list-container">
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-lcci0101/" class="wrapper post-i-link" title="LCCI 01.01.判定字符是否唯一">
|
||||
<div class="wrapper cover">
|
||||
<img src="/images/leetcode-0101.png" alt="LCCI 01.01.判定字符是否唯一">
|
||||
</div>
|
||||
<h3 class="wrapper title" title="LCCI 01.01.判定字符是否唯一">LCCI 01.01.判定字符是否唯一</h3>
|
||||
<p class="wrapper subtitle">
|
||||
LeetCode刷题计划
|
||||
</p>
|
||||
<div class="wrapper time">2020-02-25</div>
|
||||
</a>
|
||||
</li>
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-0000/" class="wrapper post-i-link" title="0000.为什么需要复杂度分析">
|
||||
<div class="wrapper cover">
|
||||
|
||||
@@ -95,6 +95,19 @@
|
||||
<div class="wrapper index-wrapper">
|
||||
<ul class="container list-container">
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-lcci0101/" class="wrapper post-i-link" title="LCCI 01.01.判定字符是否唯一">
|
||||
<div class="wrapper cover">
|
||||
<img src="/images/leetcode-0101.png" alt="LCCI 01.01.判定字符是否唯一">
|
||||
</div>
|
||||
<h3 class="wrapper title" title="LCCI 01.01.判定字符是否唯一">LCCI 01.01.判定字符是否唯一</h3>
|
||||
<p class="wrapper subtitle">
|
||||
LeetCode刷题计划
|
||||
</p>
|
||||
<div class="wrapper time">2020-02-25</div>
|
||||
</a>
|
||||
</li>
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-0000/" class="wrapper post-i-link" title="0000.为什么需要复杂度分析">
|
||||
<div class="wrapper cover">
|
||||
|
||||
156
article/python-leetcode-lcci0101/index.html
Normal file
156
article/python-leetcode-lcci0101/index.html
Normal file
@@ -0,0 +1,156 @@
|
||||
<!DOCTYPE html>
|
||||
<html lang="zh-CN">
|
||||
<head>
|
||||
<head><meta name="generator" content="Hexo 3.9.0">
|
||||
<!-- Title -->
|
||||
|
||||
<meta charset="utf-8">
|
||||
<meta name="applicable-device" content="pc,mobile">
|
||||
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=3.0, viewport-fit=cover">
|
||||
<meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
|
||||
<meta name="author" content="flypython">
|
||||
<meta name="designer" content="flypython">
|
||||
<meta name="keywords" content="LCCI 01.01.判定字符是否唯一,FlyPython - 专业的Python学习社区,flypython, 飞蟒，飞蟒Python，Python入门，Python自动化，Python日报">
|
||||
<meta property="og:title" content="LCCI 01.01.判定字符是否唯一 | FlyPython - 专业的Python学习社区">
|
||||
<meta property="og:site_name" content="http://www.flypython.com">
|
||||
|
||||
<meta property="og:type" content="article">
|
||||
<meta property="og:url" content="http://www.flypython.com/article/python-leetcode-lcci0101/">
|
||||
<meta property="og:image" content="http://www.flypython.com/images/leetcode-0101.png">
|
||||
<meta property="og:description" content="LCCI 01.01.判定字符是否唯一--LeetCode刷题计划">
|
||||
<meta name="description" content="LCCI 01.01.判定字符是否唯一--LeetCode刷题计划">
|
||||
|
||||
<meta name="rating" content="general">
|
||||
<meta name="apple-mobile-web-app-capable" content="yes">
|
||||
<meta name="apple-mobile-web-app-status-bar-style" content="black">
|
||||
<meta name="format-detection" content="telephone=yes">
|
||||
<meta name="mobile-web-app-capable" content="yes">
|
||||
<meta name="robots" content="index, follow">
|
||||
<link rel="icon" href="/images/favicon.ico">
|
||||
<title>LCCI 01.01.判定字符是否唯一 | FlyPython - 专业的Python学习社区</title>
|
||||
<link rel="stylesheet" href="/css/f25.css">
|
||||
<link rel="stylesheet" href="/css/highlight.css">
|
||||
|
||||
|
||||
<!-- Global site tag (gtag.js) - Google Analytics -->
|
||||
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-147288599-1"></script>
|
||||
<script>
|
||||
window.dataLayer = window.dataLayer || [];
|
||||
function gtag(){dataLayer.push(arguments);}
|
||||
gtag('js', new Date());
|
||||
|
||||
gtag('config', 'UA-147288599-1');
|
||||
</script>
|
||||
|
||||
</head>
|
||||
</head>
|
||||
<body>
|
||||
<header class="wrapper header-wrapper">
|
||||
<div class="container header-nav-wrapper">
|
||||
<div class="logo"><a href="/" title="FlyPython - 专业的Python学习社区"><h1 class="title">FlyPython</h1></a></div>
|
||||
<nav class="nav-wrapper">
|
||||
|
||||
<a href="https://flypython.com/python" title="飞蟒微课堂">飞蟒微课堂</a>
|
||||
|
||||
<a href="https://flypython.com/flypython_daily" title="Python日报">Python日报</a>
|
||||
|
||||
<a href="https://flypython.com/PyCon/" title="PyCon">PyCon</a>
|
||||
|
||||
<a href="https://github.com/flypythoncom" title="Github">Github</a>
|
||||
|
||||
<a href="/article/about" title="关于">关于</a>
|
||||
|
||||
</nav>
|
||||
<span class="btn-menu" id="J_header_menu">
|
||||
<div class="inner">
|
||||
<span class="line line-01"></span>
|
||||
<span class="line line-02"></span>
|
||||
<span class="line line-03"></span>
|
||||
</div>
|
||||
</span>
|
||||
<div class="wrapper mb-nav-wrapper" id="J_header_menu_list">
|
||||
<nav class="wrapper mb-nav-container">
|
||||
|
||||
<a href="https://flypython.com/python" title="飞蟒微课堂">飞蟒微课堂</a>
|
||||
|
||||
<a href="https://flypython.com/flypython_daily" title="Python日报">Python日报</a>
|
||||
|
||||
<a href="https://flypython.com/PyCon/" title="PyCon">PyCon</a>
|
||||
|
||||
<a href="https://github.com/flypythoncom" title="Github">Github</a>
|
||||
|
||||
<a href="/article/about" title="关于">关于</a>
|
||||
|
||||
</nav>
|
||||
</div>
|
||||
</div>
|
||||
</header>
|
||||
<section class="body-wrapper">
|
||||
<section class="wrapper post-banner">
|
||||
<div class="container post-banner-container">
|
||||
<h2 class="wrapper title">LCCI 01.01.判定字符是否唯一</h2>
|
||||
<div class="wrapper tips">
|
||||
<span>Author：</span><span>flypython</span> | <span>Date: </span><span>2020-02-25</span> | <span>Category：</span><span><a href="/fly/飞蟒微课堂/" title="飞蟒微课堂">飞蟒微课堂</a><a href="/fly/飞蟒微课堂/LeetCode/" title="LeetCode">LeetCode</a></span>
|
||||
</div>
|
||||
</div>
|
||||
</section>
|
||||
<section class="wrapper main-wrapper">
|
||||
<article class="sub-container post-content">
|
||||
<h2 id="01-01-判定字符是否唯一"><a href="#01-01-判定字符是否唯一" class="headerlink" title="01.01.判定字符是否唯一"></a>01.01.判定字符是否唯一</h2><p>链接：<a href="https://leetcode-cn.com/problems/is-unique-lcci/" target="_blank" rel="noopener">https://leetcode-cn.com/problems/is-unique-lcci/</a><br>难度：简单</p>
|
||||
<h4 id="题目"><a href="#题目" class="headerlink" title="题目"></a>题目</h4><blockquote>
|
||||
<p>实现一个算法，确定一个字符串 s 的所有字符是否全都不同。</p>
|
||||
<p>示例 1：</p>
|
||||
<p>输入: s = “leetcode”<br>输出: false<br>示例 2：</p>
|
||||
<p>输入: s = “abc”<br>输出: true</p>
|
||||
<p>限制：</p>
|
||||
<p>0 <= len(s) <= 100<br>如果你不使用额外的数据结构，会很加分。</p>
|
||||
</blockquote>
|
||||
<h4 id="思路"><a href="#思路" class="headerlink" title="思路"></a>思路</h4><p>首先，你得理解题意。不确定的东西，需要问或者尝试验证。</p>
|
||||
<p>比如：这里你可以问面试官字符串s是ASCII还是Unicode字符串，如果是编程平台你可以写测试来判断。</p>
|
||||
<p>在这里我们假定字符集为ASCII，那如果字符串长度大于128，那肯定是false，不过有限制条件len(s)<=100，那这个判断就不必要了。限制里面还要求不使用额外的数据结构，这就过滤掉了很多的方案。</p>
|
||||
<p>比如，使用set就一行代码解决</p>
|
||||
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">class Solution:</span><br><span class="line"> def isUnique(self, astr: str) -> bool:</span><br><span class="line"> return len(astr)== len(set(astr))</span><br></pre></td></tr></table></figure>
|
||||
|
||||
<p>我们很容易想到hash计数的方法，经过测试，字符串中只出现’a’到’z’，26个小写字母，那只需要一个bool数组，直接统计出现的频率，判断是否重复。</p>
|
||||
<p>考虑到不使用额外的数据结构，那我们可以尝试使用bitmap，把数组换成一个整型数，按照位上0，1来判断是否重复。</p>
|
||||
<p>开始我们算出字符离最开始的字符’a’的距离，然后1移动这个距离来表示这个数。后面用一个测试变量来测试p，如果存在则返回False，如果不存在则写入。</p>
|
||||
<p>具体代码：</p>
|
||||
<pre><code>def isUnique(self, astr: str) -> bool:
|
||||
t = 0
|
||||
for c in astr:
|
||||
if t & (p := 1 << (ord(c) - ord('a'))):
|
||||
return False
|
||||
t |= p
|
||||
return True</code></pre><p>在解答中使用了Python3.8的新特性：海象运算符，点击下面的链接，学习使用它。<br><a href="https://mp.weixin.qq.com/s/3xKdt-26guYHoFb3xP0muw" target="_blank" rel="noopener">https://mp.weixin.qq.com/s/3xKdt-26guYHoFb3xP0muw</a></p>
|
||||
<h4 id="方案代码"><a href="#方案代码" class="headerlink" title="方案代码"></a>方案代码</h4><p>解法:</p>
|
||||
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line">class Solution:</span><br><span class="line"> def isUnique(self, astr: str) -> bool:</span><br><span class="line"> t = 0</span><br><span class="line"> for c in astr:</span><br><span class="line"> if t & (p := 1 << (ord(c) - ord('a'))):</span><br><span class="line"> return False</span><br><span class="line"> t |= p</span><br><span class="line"> return True</span><br></pre></td></tr></table></figure>
|
||||
|
||||
<p>另外还有三种使用数据结构的解法</p>
|
||||
<p>解法1:</p>
|
||||
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">class Solution:</span><br><span class="line"> def isUnique(self, astr: str) -> bool:</span><br><span class="line"> return len(astr)== len(set(astr))</span><br></pre></td></tr></table></figure>
|
||||
|
||||
<p>解法2:</p>
|
||||
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">class Solution:</span><br><span class="line"> def isUnique(self, astr: str) -> bool:</span><br><span class="line"> adict={}</span><br><span class="line"> for value in astr:</span><br><span class="line"> if value in adict.keys():</span><br><span class="line"> return False</span><br><span class="line"> else:</span><br><span class="line"> adict[value]=0</span><br><span class="line"> return True</span><br></pre></td></tr></table></figure>
|
||||
|
||||
<p>解法3:</p>
|
||||
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">class Solution:</span><br><span class="line"> def isUnique(self, astr: str) -> bool:</span><br><span class="line"> l=[]</span><br><span class="line"> for i in astr:</span><br><span class="line"> if i in l:</span><br><span class="line"> return False</span><br><span class="line"> else:</span><br><span class="line"> l.append(i)</span><br><span class="line"> return True</span><br></pre></td></tr></table></figure>
|
||||
|
||||
|
||||
</article>
|
||||
<div class="sub-container gitalk-wrapper" id="gitalk-container"></div>
|
||||
</section>
|
||||
|
||||
<div class="tips-top-wrapper">
|
||||
<span class="tip-top-container" onclick="scrollToWindowTop()">
|
||||
<span class="l-bar"></span>
|
||||
<span class="r-bar"></span>
|
||||
</span>
|
||||
</div>
|
||||
<footer class="wrapper footer-wrapper">
|
||||
<div class="container"><span class="copyright">© 2020 FlyPython . All Rights Reserved.</span></div>
|
||||
</footer>
|
||||
</section>
|
||||
<script src="/js/f25.js"></script>
|
||||
|
||||
</body>
|
||||
</html>
|
||||
@@ -95,6 +95,19 @@
|
||||
<div class="wrapper index-wrapper">
|
||||
<ul class="container list-container">
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-lcci0101/" class="wrapper post-i-link" title="LCCI 01.01.判定字符是否唯一">
|
||||
<div class="wrapper cover">
|
||||
<img src="/images/leetcode-0101.png" alt="LCCI 01.01.判定字符是否唯一">
|
||||
</div>
|
||||
<h3 class="wrapper title" title="LCCI 01.01.判定字符是否唯一">LCCI 01.01.判定字符是否唯一</h3>
|
||||
<p class="wrapper subtitle">
|
||||
LeetCode刷题计划
|
||||
</p>
|
||||
<div class="wrapper time">2020-02-25</div>
|
||||
</a>
|
||||
</li>
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-0000/" class="wrapper post-i-link" title="0000.为什么需要复杂度分析">
|
||||
<div class="wrapper cover">
|
||||
|
||||
@@ -95,6 +95,19 @@
|
||||
<div class="wrapper index-wrapper">
|
||||
<ul class="container list-container">
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-lcci0101/" class="wrapper post-i-link" title="LCCI 01.01.判定字符是否唯一">
|
||||
<div class="wrapper cover">
|
||||
<img src="/images/leetcode-0101.png" alt="LCCI 01.01.判定字符是否唯一">
|
||||
</div>
|
||||
<h3 class="wrapper title" title="LCCI 01.01.判定字符是否唯一">LCCI 01.01.判定字符是否唯一</h3>
|
||||
<p class="wrapper subtitle">
|
||||
LeetCode刷题计划
|
||||
</p>
|
||||
<div class="wrapper time">2020-02-25</div>
|
||||
</a>
|
||||
</li>
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-0000/" class="wrapper post-i-link" title="0000.为什么需要复杂度分析">
|
||||
<div class="wrapper cover">
|
||||
|
||||
BIN
images/leetcode-0101.png
Normal file
BIN
images/leetcode-0101.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 497 KiB |
13
index.html
13
index.html
@@ -95,6 +95,19 @@
|
||||
<div class="wrapper index-wrapper">
|
||||
<ul class="container list-container">
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-lcci0101/" class="wrapper post-i-link" title="LCCI 01.01.判定字符是否唯一">
|
||||
<div class="wrapper cover">
|
||||
<img src="/images/leetcode-0101.png" alt="LCCI 01.01.判定字符是否唯一">
|
||||
</div>
|
||||
<h3 class="wrapper title" title="LCCI 01.01.判定字符是否唯一">LCCI 01.01.判定字符是否唯一</h3>
|
||||
<p class="wrapper subtitle">
|
||||
LeetCode刷题计划
|
||||
</p>
|
||||
<div class="wrapper time">2020-02-25</div>
|
||||
</a>
|
||||
</li>
|
||||
|
||||
<li class="post-i-wrapper">
|
||||
<a href="/article/python-leetcode-0000/" class="wrapper post-i-link" title="0000.为什么需要复杂度分析">
|
||||
<div class="wrapper cover">
|
||||
|
||||
Reference in New Issue
Block a user