{"id":411,"date":"2025-09-26T17:49:08","date_gmt":"2025-09-26T09:49:08","guid":{"rendered":"https:\/\/heyingnian.com\/?p=411"},"modified":"2025-09-26T18:13:15","modified_gmt":"2025-09-26T10:13:15","slug":"leetcode-104","status":"publish","type":"post","link":"https:\/\/heyingnian.com\/index.php\/2025\/09\/26\/leetcode-104\/","title":{"rendered":"\u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6"},"content":{"rendered":"\n

\ud83d\udd17 \u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6<\/h1>\n\n\n\n

\u9898\u76ee\u6765\u6e90\uff1a104. \u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6 – \u529b\u6263\uff08LeetCode\uff09<\/a><\/p>\n\n\n\n

\ud83d\udccc \u9898\u76ee\u63cf\u8ff0<\/p>\n\n\n\n

\u7ed9\u5b9a\u4e00\u4e2a\u4e8c\u53c9\u6811 root<\/code>\uff0c\u8fd4\u56de\u5176\u6700\u5927\u6df1\u5ea6\u3002<\/p>\n\n\n\n

\u4e8c\u53c9\u6811\u7684 \u6700\u5927\u6df1\u5ea6<\/strong> \u662f\u6307\u4ece\u6839\u8282\u70b9\u5230\u6700\u8fdc\u53f6\u5b50\u8282\u70b9\u7684\u6700\u957f\u8def\u5f84\u4e0a\u7684\u8282\u70b9\u6570\u3002<\/p>\n\n\n\n

\u2705 \u793a\u4f8b\u89e3\u6790<\/p>\n\n\n\n

\u793a\u4f8b 1\uff1a<\/strong><\/p>\n\n\n\n

\"\"<\/div><\/figure>\n\n\n\n

\u8f93\u5165\uff1aroot = [3,9,20,null,null,15,7]<\/code>
\u8f93\u51fa\uff1a3<\/code>
\u89e3\u91ca\uff1a\u4ece\u6839\u8282\u70b9 3 \u51fa\u53d1\uff0c\u6700\u957f\u8def\u5f84\u4e3a 3 \u2192 20 \u2192 15\uff08\u6216 7\uff09\uff0c\u5171 3 \u4e2a\u8282\u70b9\u3002<\/p>\n\n\n\n

\u793a\u4f8b 2\uff1a<\/strong><\/p>\n\n\n\n

\u8f93\u5165\uff1aroot = [1,null,2]<\/code>
\u8f93\u51fa\uff1a2<\/code>
\u89e3\u91ca\uff1a\u8def\u5f84\u4e3a 1 \u2192 2\uff0c\u5171 2 \u4e2a\u8282\u70b9\u3002<\/p>\n\n\n\n

\u793a\u4f8b 3\uff1a<\/strong><\/p>\n\n\n\n

\u8f93\u5165\uff1aroot = []<\/code>
\u8f93\u51fa\uff1a0<\/code>
\u89e3\u91ca\uff1a\u7a7a\u6811\u6ca1\u6709\u8282\u70b9\uff0c\u6df1\u5ea6\u4e3a 0\u3002<\/p>\n\n\n\n

\u26a0\ufe0f \u63d0\u793a<\/p>\n\n\n\n

    \n
  • \u6811\u4e2d\u8282\u70b9\u7684\u6570\u91cf\u5728\u00a0[0, 10\u2074]<\/code>\u00a0\u533a\u95f4\u5185\u3002<\/li>\n\n\n\n
  • -100 <= Node.val <= 100<\/code><\/li>\n<\/ul>\n\n\n\n

    \ud83d\udca1 \u89e3\u6cd5\uff1a\u6df1\u5ea6\u4f18\u5148\u641c\u7d22\uff08DFS\uff09\u9012\u5f52 \u2014\u2014 O(n) \u65f6\u95f4\uff0cO(h) \u7a7a\u95f4<\/p>\n\n\n\n

    class Solution {\n    public int maxDepth(TreeNode root) {\n        return dfs(root);\n    }\n\n    public int dfs(TreeNode root) {\n        if (root == null) {\n            return 0;\n        }\n        int left = dfs(root.left);\n        int right = dfs(root.right);\n        return Math.max(left, right) + 1;\n    }\n}<\/code><\/pre>\n\n\n\n
    \ud83d\udcca \u590d\u6742\u5ea6\u5206\u6790<\/p>\n\n\n\n
      \n
    • \u65f6\u95f4\u590d\u6742\u5ea6\uff1aO(n)<\/strong>
      \u6bcf\u4e2a\u8282\u70b9\u6070\u597d\u88ab\u8bbf\u95ee\u4e00\u6b21\uff0c\u603b\u5171\u6709 n \u4e2a\u8282\u70b9\uff0c\u56e0\u6b64\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a O(n)\u3002<\/li>\n\n\n\n
    • \u7a7a\u95f4\u590d\u6742\u5ea6\uff1aO(h)<\/strong>
      \u9012\u5f52\u8c03\u7528\u6808\u7684\u6df1\u5ea6\u7b49\u4e8e\u6811\u7684\u9ad8\u5ea6 h\u3002\u6700\u574f\u60c5\u51b5\u4e0b\uff08\u6811\u9000\u5316\u4e3a\u94fe\u8868\uff09\uff0ch = n\uff1b\u6700\u597d\u60c5\u51b5\u4e0b\uff08\u5b8c\u5168\u5e73\u8861\u6811\uff09\uff0ch = log n\u3002\u56e0\u6b64\u7a7a\u95f4\u590d\u6742\u5ea6\u4e3a O(h)\u3002<\/li>\n<\/ul>\n\n\n\n
      \ud83e\udde9 \u89e3\u9898\u601d\u8def<\/p>\n\n\n\n
      \u9012\u5f52\u601d\u60f3\uff1a<\/strong>
      \u4e00\u68f5\u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6 = 1\uff08\u5f53\u524d\u6839\u8282\u70b9\uff09 + \u5de6\u53f3\u5b50\u6811\u4e2d\u6df1\u5ea6\u8f83\u5927\u7684\u90a3\u4e2a\u3002<\/p>\n\n\n\n
      \u6838\u5fc3\u903b\u8f91\uff1a<\/strong><\/p>\n\n\n\n
        \n
      • \u5982\u679c\u5f53\u524d\u8282\u70b9\u4e3a\u7a7a\uff0c\u8fd4\u56de\u6df1\u5ea6 0\u3002<\/li>\n\n\n\n
      • \u5426\u5219\uff0c\u5206\u522b\u9012\u5f52\u8ba1\u7b97\u5de6\u5b50\u6811\u548c\u53f3\u5b50\u6811\u7684\u6df1\u5ea6\u3002<\/li>\n\n\n\n
      • \u53d6\u4e24\u8005\u6700\u5927\u503c\u52a0 1\uff0c\u5373\u4e3a\u5f53\u524d\u6811\u7684\u6df1\u5ea6\u3002<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
        \ud83d\udd17 \u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6 \u9898\u76ee\u6765\u6e90\uff1a104. \u4e8c\u53c9\u6811\u7684\u6700\u5927\u6df1\u5ea6 – \u529b\u6263\uff08LeetCode\uff09 \ud83d\udccc \u9898\u76ee […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[39,12],"tags":[57,58,14],"class_list":["post-411","post","type-post","status-publish","format-standard","hentry","category-binary_tree","category-algorithm","tag-binary_tree","tag-dfs","tag-algorithm"],"_links":{"self":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/411","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/comments?post=411"}],"version-history":[{"count":1,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/411\/revisions"}],"predecessor-version":[{"id":413,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/411\/revisions\/413"}],"wp:attachment":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/media?parent=411"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/categories?post=411"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/tags?post=411"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}