{"id":507,"date":"2020-09-26T10:50:07","date_gmt":"2020-09-26T02:50:07","guid":{"rendered":"http:\/\/39.96.58.60\/?p=507"},"modified":"2022-10-18T16:39:03","modified_gmt":"2022-10-18T08:39:03","slug":"leetcode-5-%e6%9c%80%e9%95%bf%e5%9b%9e%e6%96%87%e5%ad%90%e4%b8%b2","status":"publish","type":"post","link":"http:\/\/www.yatenglg.cn\/blog\/?p=507","title":{"rendered":"Leetcode 5. \u6700\u957f\u56de\u6587\u5b50\u4e32"},"content":{"rendered":"<p>\u7ed9\u5b9a\u4e00\u4e2a\u5b57\u7b26\u4e32 <code>s<\/code>\uff0c\u627e\u5230 <code>s<\/code> \u4e2d\u6700\u957f\u7684\u56de\u6587\u5b50\u4e32\u3002\u4f60\u53ef\u4ee5\u5047\u8bbe&nbsp;<code>s<\/code> \u7684\u6700\u5927\u957f\u5ea6\u4e3a 1000\u3002<\/p>\n<p><strong>\u793a\u4f8b 1\uff1a<\/strong><\/p>\n<pre><strong>\u8f93\u5165:<\/strong> \"babad\"\n\n<strong>\u8f93\u51fa:<\/strong> \"bab\"\n\n<strong>\u6ce8\u610f:<\/strong> \"aba\" \u4e5f\u662f\u4e00\u4e2a\u6709\u6548\u7b54\u6848\u3002\n\n<\/pre>\n<p><strong>\u793a\u4f8b 2\uff1a<\/strong><\/p>\n<pre><strong>\u8f93\u5165:<\/strong> \"cbbd\"\n\n<strong>\u8f93\u51fa:<\/strong> \"bb\"\n\n<\/pre>\n<p>**\u96be\u5ea6**: Medium<\/p>\n<p>**\u6807\u7b7e**: \u5b57\u7b26\u4e32\u3001 \u52a8\u6001\u89c4\u5212\u3001<\/p>\n<div class=\"hcb_wrap\">\n<pre class=\"prism undefined-numbers lang-python\" data-lang=\"Python\"><code>\n# -*- coding: utf-8 -*-\n# @Author  : LG\n\"\"\"\n\u6267\u884c\u7528\u65f6\uff1a804 ms, \u5728\u6240\u6709 Python3 \u63d0\u4ea4\u4e2d\u51fb\u8d25\u4e8687.08% \u7684\u7528\u6237\n\u5185\u5b58\u6d88\u8017\uff1a13.5 MB, \u5728\u6240\u6709 Python3 \u63d0\u4ea4\u4e2d\u51fb\u8d25\u4e869.26% \u7684\u7528\u6237\n\n\u7b97\u6cd5\u601d\u60f3\uff1a\n    \u4f7f\u7528\u4e86\u4e2d\u5fc3\u6269\u6563\u7684\u601d\u60f3\uff1a\n    \u5177\u4f53\u5b9e\u73b0\u89c1\u4ee3\u7801\u6ce8\u91ca\n\n\u6ce8\uff1a Manacher \u7b97\u6cd5 \u901f\u5ea6\u66f4\u5feb\uff0c\u4f46\u66f4\u4e3a\u590d\u6742\uff0c\u6709\u5174\u8da3\u53ef\u4ee5\u4e86\u89e3\u4e00\u4e0b\n\"\"\"\n\nclass Solution:\n    def longestPalindrome(self, s: str) -&gt; str:\n        n = len(s)\n        string = \"\"\n\n        for m in range(n):  # \u4ece\u5b57\u7b26\u4e32\u8d77\u59cb\u5f00\u59cb\u8fdb\u884c\u904d\u5386\uff0cm\u4e3a\u5f53\u524d\u5b57\u7b26\u4e32\u4e2d\u5fc3\uff0c \u4f46\u5b57\u7b26\u5fc5\u5b9a\u56de\u6587\n            p, q = m, m     # \u521d\u59cb\u4fe9\u4e2a\u6307\u9488\uff0c\u6307\u5411\u8be5\u56de\u6587\u5b57\u7b26\uff0c\u4e24\u6307\u9488\u4f1a\u4e00\u4e2a\u5de6\u79fb\u3001\u4e00\u4e2a\u53f3\u79fb\uff0c\u7528\u4e8e\u5224\u65ad\u6269\u6563\u540e\u7684\u5b57\u7b26\u4e32\u662f\u5426\u56de\u6587\n            while s[q] == s[m]: # \u5224\u65ad\u8be5\u5b57\u7b26\u76f8\u90bb\u5b57\u7b26\u662f\u5426\u76f8\u7b49\uff0c\u82e5\u76f8\u7b49\uff0c\u5219\u5c06\u53f3\u6307\u9488\u53f3\u79fb\u3002\u8fd9\u662f\u4e3a\u4e86\u5904\u7406abba\u5f62\u5f0f\uff0c\u4ee5bb\u4e3a\u4e2d\u5fc3\u7684\u5076\u6570\u56de\u6587\n                q += 1\n                if q &gt; n-1:\n                    break\n            q -= 1\n\n            while s[p] == s[q]: # \u5224\u65ad\u4e24\u6307\u9488\u6240\u6307\u5b57\u7b26\u662f\u5426\u76f8\u7b49\uff0c\u82e5\u76f8\u7b49\uff0c\u5219\u6307\u9488\u5185\u90e8\u5b57\u7b26\u4e32\u56de\u6587\uff0c\u6307\u9488\u6269\u6563\n                p -= 1\n                q += 1\n                if (p &lt; 0) or (q &gt; n-1):    # \u6307\u9488\u8d85\u51fa\u5b57\u7b26\u4e32\u7d22\u5f15\uff0c\u8df3\u51fa\u5faa\u73af\n                    break\n            if len(string) &lt; q-p-1: # \u5bf9\u6bd4\u5f53\u524d\u6307\u9488\u5185\u90e8\u5b57\u7b26\u4e32\u4e0e\u8bb0\u5f55\u7684\u56de\u6587\u5b57\u7b26\u4e32\n                string = s[p+1:q]\n        return string\n\n\n\"\"\"\n\u6267\u884c\u7528\u65f6\uff1a4852 ms, \u5728\u6240\u6709 Python3 \u63d0\u4ea4\u4e2d\u51fb\u8d25\u4e8632.82% \u7684\u7528\u6237\n\u5185\u5b58\u6d88\u8017\uff1a21.4 MB, \u5728\u6240\u6709 Python3 \u63d0\u4ea4\u4e2d\u51fb\u8d25\u4e865.55% \u7684\u7528\u6237\n\n\u89e3\u9898\u601d\u8def\uff1a\n    \u4f7f\u7528\u4e86\u52a8\u6001\u89c4\u5212\u7684\u601d\u60f3\u3002\n    \u5177\u4f53\u770b\u4ee3\u7801\u6ce8\u91ca\n\"\"\"\n\nclass Solution:\n    def longestPalindrome(self, s: str) -&gt; str:\n        n = len(s)\n        string = \"\"\n        dp = [[False] * n for _ in range(n)]    # \u4e00\u4e2a\u77e9\u9635\uff0c\u7528\u4e8e\u5b58\u50a8\u5bf9\u4e8e \u8d77\u59cb\u4e0b\u6807i\u5230\u7ed3\u5c3e\u4e0b\u6807j\u5bf9\u5e94\u5b57\u7b26\u4e32 \u662f\u5426\u56de\u6587\n\n        for j in range(n):  # \u4ece\u5f00\u59cb\u4e00\u6b21\u904d\u5386 0, 1, 2, ... ,n\n            for i in range(j+1):    # \u53ea\u9700\u904d\u5386\u4e00\u534a\uff0c\u4e0b\u6807(i, j)\uff1a(0, 0), (0, 1), (1, 1), (0, 2), (1, 2), ...\n                if i == j:          # \u5bf9\u89d2\u7ebf\u4e3a\u5355\u5b57\u7b26\uff0c\u5fc5\u5b9a\u56de\u6587\n                    dp[i][j] = True\n                if j-i &gt; 2:         # \u82e5\u4e0b\u6807\u95f4\u8ddd\u5927\u4e8e2\uff0c \u5373abaa\uff0c \u4e0b\u6807\u4e2d\u95f4\u4e0d\u6b62\u4e00\u4e2a\u5b57\u7b26\uff0c\u5219\u5224\u65ad\u4fe9\u5b57\u7b26\u662f\u5426\u76f8\u7b49\uff0c\u4e14\u4e2d\u95f4\u90e8\u5206\u662f\u5426\u56de\u6587\n                    dp[i][j] = (((s[i] == s[j]) and dp[i+1][j-1]))\n                else:               # \u82e5\u4e0b\u6807\u95f4\u8ddd\u4e0d\u5927\u4e8e2\uff0c\u5373aba\uff0c \u5219\u53ea\u9700\u5224\u65ad\u4e0b\u6807\u5bf9\u5e94\u5b57\u7b26\u662f\u5426\u76f8\u7b49\u5373\u53ef\u5224\u65ad\u662f\u5426\u56de\u6587\n                    dp[i][j] = (s[i] == s[j])\n                if dp[i][j] and j+1-i &gt; len(string):    # \u82e5\u5f53\u524d\u4e0b\u6807\u95f4\u7684\u5b57\u7b26\u4e32\u56de\u6587\uff0c\u5219\u5bf9\u6bd4\u8bb0\u5f55\u7684\u5b57\u7b26\u4e32\uff0c\u4e14\u6bd4\u8f83\u957f\u5ea6\n                    string = s[i: j+1]\n        return string<\/code><\/pre>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u7ed9\u5b9a\u4e00\u4e2a\u5b57\u7b26\u4e32 s\uff0c\u627e\u5230 s \u4e2d\u6700\u957f\u7684\u56de\u6587\u5b50\u4e32\u3002\u4f60\u53ef\u4ee5\u5047\u8bbe&nbsp;s \u7684\u6700\u5927\u957f\u5ea6\u4e3a 1000\u3002 \u793a\u4f8b 1\uff1a&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":[],"categories":[11,1],"tags":[],"_links":{"self":[{"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=\/wp\/v2\/posts\/507"}],"collection":[{"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=507"}],"version-history":[{"count":1,"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=\/wp\/v2\/posts\/507\/revisions"}],"predecessor-version":[{"id":508,"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=\/wp\/v2\/posts\/507\/revisions\/508"}],"wp:attachment":[{"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=507"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=507"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.yatenglg.cn\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=507"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}