<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet href="/rss/styles.xsl" type="text/xsl"?><rss version="2.0"><channel><title>BigO</title><description>在这里，我们死磕时间与空间复杂度。探寻算法的最优解，重学那些被忽略的计算机底层常识。</description><link>https://chirping-astro.example.com/</link><language>en-us</language><item><title>折磨</title><link>https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E6%8A%98%E7%A3%A8/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E6%8A%98%E7%A3%A8/</guid><description>在一个无向社交网络中，已知每名用户的心动价位及初始发出“瓜条”的源头节点（当用户看到不低于自身心动价位的瓜条时会转发并更新心动价位，引发扩散），计算为使指定节点（猫猫）完全接收不到任何瓜条，最少需要屏蔽猫猫的多少个直接好友。</description><pubDate>Sat, 01 Aug 2026 14:00:00 GMT</pubDate><category>Dijkstra 算法</category><category>题库</category></item><item><title>线网建设</title><link>https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E7%BA%BF%E7%BD%91%E5%BB%BA%E8%AE%BE/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E7%BA%BF%E7%BD%91%E5%BB%BA%E8%AE%BE/</guid><description>给定二维平面上的 n 座基站坐标，只有当两点间欧氏距离不超过给定上限 l 时才能建路。要求判断能否使所有基站连通，若能，求连通所有基站所需的最小线路总长度（保留两位小数）；若不能，则输出 Impossible。</description><pubDate>Mon, 29 Jun 2026 00:00:00 GMT</pubDate><category>Prim 算法</category><category>题库</category></item><item><title>菱形</title><link>https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E8%8F%B1%E5%BD%A2/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E8%8F%B1%E5%BD%A2/</guid><description>给定一个大于 1 的奇数 n，要求按规则输出一个 n 行 n 列的字符画。</description><pubDate>Tue, 30 Sep 2025 00:00:00 GMT</pubDate><category>题库</category></item><item><title>数位和</title><link>https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E6%95%B0%E4%BD%8D%E5%92%8C/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E6%95%B0%E4%BD%8D%E5%92%8C/</guid><description>给定 n 个不超过 10^12 的正整数，求这 n 个正整数中数位和（即各数位数字相加的总和）的最大值。</description><pubDate>Sat, 07 Dec 2024 00:00:00 GMT</pubDate><category>数位分离</category><category>题库</category></item><item><title>重要的城市</title><link>https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E9%87%8D%E8%A6%81%E7%9A%84%E5%9F%8E%E5%B8%82/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E9%A2%98%E5%BA%93/%E9%87%8D%E8%A6%81%E7%9A%84%E5%9F%8E%E5%B8%82/</guid><description>本题要求在一张无向加权图中寻找所有重要城市：若摧毁某节点会导致至少一对其他节点之间的最短路径变长或不可达，则称该节点为重要城市。</description><pubDate>Thu, 01 Feb 2007 00:00:00 GMT</pubDate><category>动态规划</category><category>Floyd-Warshall 算法</category><category>题库</category></item><item><title>递归</title><link>https://chirping-astro.example.com/posts/%E7%AE%97%E6%B3%95%E8%AE%BE%E8%AE%A1/%E9%80%92%E5%BD%92/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E7%AE%97%E6%B3%95%E8%AE%BE%E8%AE%A1/%E9%80%92%E5%BD%92/</guid><description>递归是一种通过函数调用自身来解决问题的编程技巧，其核心在于具备终止条件与递归步骤，通过将大问题拆解为规模更小的子问题逐步求解，但也需注意避免因重复计算导致的性能陷阱。</description><pubDate>Mon, 01 Jan 1990 00:00:02 GMT</pubDate><category>算法设计</category></item><item><title>穷举</title><link>https://chirping-astro.example.com/posts/%E7%AE%97%E6%B3%95%E8%AE%BE%E8%AE%A1/%E7%A9%B7%E4%B8%BE/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E7%AE%97%E6%B3%95%E8%AE%BE%E8%AE%A1/%E7%A9%B7%E4%B8%BE/</guid><description>穷举搜索（暴力搜索）是一种通过无遗漏地列举并检验解空间中的每一个候选解，以算力换取解法正确性的基础计算机求解策略。</description><pubDate>Mon, 01 Jan 1990 00:00:01 GMT</pubDate><category>算法设计</category></item><item><title>Floyd-Warshall 算法</title><link>https://chirping-astro.example.com/posts/%E6%9C%80%E7%9F%AD%E8%B7%AF%E5%BE%84%E9%97%AE%E9%A2%98/floyd-warshall-%E7%AE%97%E6%B3%95/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E6%9C%80%E7%9F%AD%E8%B7%AF%E5%BE%84%E9%97%AE%E9%A2%98/floyd-warshall-%E7%AE%97%E6%B3%95/</guid><description>Floyd‑Warshall 算法是基于动态规划的全源最短路径算法，可求解图中任意两点最短距离，支持负权边，适合小规模稠密图，也能够检测图中的负权环。</description><pubDate>Fri, 01 Jun 1962 00:00:00 GMT</pubDate><category>图</category><category>动态规划</category><category>基础算法</category><category>最短路径问题</category></item><item><title>Dijkstra 算法</title><link>https://chirping-astro.example.com/posts/%E6%9C%80%E7%9F%AD%E8%B7%AF%E5%BE%84%E9%97%AE%E9%A2%98/dijkstra-%E7%AE%97%E6%B3%95/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E6%9C%80%E7%9F%AD%E8%B7%AF%E5%BE%84%E9%97%AE%E9%A2%98/dijkstra-%E7%AE%97%E6%B3%95/</guid><description>Dijkstra 算法是图论中经典的贪心算法，依托松弛操作求解非负边权带权图的单源最短路径，广泛运用于路径规划、网络路由等各类工程场景。</description><pubDate>Tue, 01 Dec 1959 00:00:00 GMT</pubDate><category>图</category><category>贪心</category><category>基础算法</category><category>最短路径问题</category></item><item><title>汉诺塔问题</title><link>https://chirping-astro.example.com/posts/%E5%9F%BA%E7%A1%80%E7%AE%97%E6%B3%95/%E6%B1%89%E8%AF%BA%E5%A1%94%E9%97%AE%E9%A2%98/</link><guid isPermaLink="true">https://chirping-astro.example.com/posts/%E5%9F%BA%E7%A1%80%E7%AE%97%E6%B3%95/%E6%B1%89%E8%AF%BA%E5%A1%94%E9%97%AE%E9%A2%98/</guid><description>汉诺塔是一个经典的数学谜题，其核心在于运用递归思维，在遵循“大盘不能压小盘、一次只移一片”等规则下，将整体移动过程拆解为规模更小的子问题，最终把所有圆盘原样转移到目标柱。</description><pubDate>Sat, 01 Sep 1883 00:00:00 GMT</pubDate><category>递归</category><category>基础算法</category></item><item><title>欧几里得算法</title><link>https://chirping-astro.example.com/posts/%E5%9F%BA%E7%A1%80%E7%AE%97%E6%B3%95/%E6%AC%A7%E5%87%A0%E9%87%8C%E5%BE%97%E7%AE%97%E6%B3%95/</link><guid 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