https://yosgi.github.io/zh/categories/algorithms/Recent content in Algorithms on YosgiHugozhThu, 08 Oct 2026 01:31:26 +0000https://yosgi.github.io/zh/post/1104-%E4%BA%8C%E5%8F%89%E6%A0%91%E5%AF%BB%E8%B7%AF/Thu, 29 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/1104-%E4%BA%8C%E5%8F%89%E6%A0%91%E5%AF%BB%E8%B7%AF/利用之字形编号二叉树每层的对称性直接推算路径。https://yosgi.github.io/zh/post/%E5%8F%8D%E8%BD%AC%E9%93%BE%E8%A1%A82/Fri, 23 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/%E5%8F%8D%E8%BD%AC%E9%93%BE%E8%A1%A82/借助虚拟头结点原地反转链表的指定区间，并记录边界节点重新连接。https://yosgi.github.io/zh/post/1893-%E6%A3%80%E6%9F%A5%E6%98%AF%E5%90%A6%E5%8C%BA%E5%9F%9F%E5%86%85%E6%89%80%E6%9C%89%E6%95%B4%E6%95%B0%E9%83%BD%E8%A2%AB%E8%A6%86%E7%9B%96/Fri, 23 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/1893-%E6%A3%80%E6%9F%A5%E6%98%AF%E5%90%A6%E5%8C%BA%E5%9F%9F%E5%86%85%E6%89%80%E6%9C%89%E6%95%B4%E6%95%B0%E9%83%BD%E8%A2%AB%E8%A6%86%E7%9B%96/判断若干区间是否完整覆盖目标区间，从暴力解法到区间压缩优化。https://yosgi.github.io/zh/post/138-%E5%A4%8D%E5%88%B6%E5%B8%A6%E9%9A%8F%E6%9C%BA%E6%8C%87%E9%92%88%E7%9A%84%E9%93%BE%E8%A1%A8/Thu, 22 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/138-%E5%A4%8D%E5%88%B6%E5%B8%A6%E9%9A%8F%E6%9C%BA%E6%8C%87%E9%92%88%E7%9A%84%E9%93%BE%E8%A1%A8/用哈希表建立新旧节点映射来深拷贝带随机指针的链表。https://yosgi.github.io/zh/post/684-%E5%86%97%E4%BD%99%E8%BF%9E%E6%8E%A5/Wed, 07 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/684-%E5%86%97%E4%BD%99%E8%BF%9E%E6%8E%A5/用并查集模板找出使图成环的冗余边。https://yosgi.github.io/zh/post/1202-%E4%BA%A4%E6%8D%A2%E5%AD%97%E7%AC%A6%E4%B8%B2%E4%B8%AD%E7%9A%84%E5%85%83%E7%B4%A0/Tue, 06 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/1202-%E4%BA%A4%E6%8D%A2%E5%AD%97%E7%AC%A6%E4%B8%B2%E4%B8%AD%E7%9A%84%E5%85%83%E7%B4%A0/用并查集把可交换的下标分组，组内排序得到字典序最小的字符串。https://yosgi.github.io/zh/post/778-%E6%B0%B4%E4%BD%8D%E4%B8%8A%E5%8D%87%E7%9A%84%E6%B3%B3%E6%B1%A0%E4%B8%AD%E6%B8%B8%E6%B3%B3/Mon, 05 Jul 2021 00:00:00 +1200https://yosgi.github.io/zh/post/778-%E6%B0%B4%E4%BD%8D%E4%B8%8A%E5%8D%87%E7%9A%84%E6%B3%B3%E6%B1%A0%E4%B8%AD%E6%B8%B8%E6%B3%B3/二分水位并用 DFS 判断连通性，求横渡上升泳池的最短时间。https://yosgi.github.io/zh/post/475-%E4%BE%9B%E6%9A%96%E5%99%A8/Thu, 10 Jun 2021 00:00:00 +1200https://yosgi.github.io/zh/post/475-%E4%BE%9B%E6%9A%96%E5%99%A8/对每个房屋二分查找最近的供暖器，求能覆盖所有房屋的最小供暖半径。https://yosgi.github.io/zh/post/875-%E7%88%B1%E5%90%83%E9%A6%99%E8%95%89%E7%9A%84%E7%8F%82%E7%8F%82/Wed, 28 Apr 2021 00:00:00 +1200https://yosgi.github.io/zh/post/875-%E7%88%B1%E5%90%83%E9%A6%99%E8%95%89%E7%9A%84%E7%8F%82%E7%8F%82/在可能的吃香蕉速度区间上搜索，求出限定时间内吃完的最小速度。https://yosgi.github.io/zh/post/295-%E6%95%B0%E6%8D%AE%E6%B5%81%E7%9A%84%E4%B8%AD%E4%BD%8D%E6%95%B0/Wed, 24 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/295-%E6%95%B0%E6%8D%AE%E6%B5%81%E7%9A%84%E4%B8%AD%E4%BD%8D%E6%95%B0/用一个大顶堆和一个小顶堆维护数据流的实时中位数。https://yosgi.github.io/zh/post/865-%E5%85%B7%E6%9C%89%E6%89%80%E6%9C%89%E6%9C%80%E6%B7%B1%E8%8A%82%E7%82%B9%E7%9A%84%E6%9C%80%E5%B0%8F%E5%AD%90%E6%A0%91/Sun, 21 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/865-%E5%85%B7%E6%9C%89%E6%89%80%E6%9C%89%E6%9C%80%E6%B7%B1%E8%8A%82%E7%82%B9%E7%9A%84%E6%9C%80%E5%B0%8F%E5%AD%90%E6%A0%91/用一次自底向上的递归返回子树深度，找到包含所有最深节点的最小子树。https://yosgi.github.io/zh/post/1046-%E6%9C%80%E5%90%8E%E4%B8%80%E5%9D%97%E7%9F%B3%E5%A4%B4%E7%9A%84%E9%87%8D%E9%87%8F/Sun, 21 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/1046-%E6%9C%80%E5%90%8E%E4%B8%80%E5%9D%97%E7%9F%B3%E5%A4%B4%E7%9A%84%E9%87%8D%E9%87%8F/用大顶堆反复粉碎最重的两块石头，模拟最后一块石头的重量。https://yosgi.github.io/zh/post/783-%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91%E8%8A%82%E7%82%B9%E6%9C%80%E5%B0%8F%E8%B7%9D%E7%A6%BB/Thu, 18 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/783-%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91%E8%8A%82%E7%82%B9%E6%9C%80%E5%B0%8F%E8%B7%9D%E7%A6%BB/利用二叉搜索树中序遍历的有序性求相邻节点的最小差值。https://yosgi.github.io/zh/post/814-%E4%BA%8C%E5%8F%89%E6%A0%91%E5%89%AA%E6%9E%9D/Wed, 17 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/814-%E4%BA%8C%E5%8F%89%E6%A0%91%E5%89%AA%E6%9E%9D/后序遍历剪去不含 1 的子树，并用虚拟父节点使根也能被剪。https://yosgi.github.io/zh/post/1448-%E7%BB%9F%E8%AE%A1%E4%BA%8C%E5%8F%89%E6%A0%91%E4%B8%AD%E5%A5%BD%E8%8A%82%E7%82%B9%E7%9A%84%E6%95%B0%E7%9B%AE/Wed, 17 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/1448-%E7%BB%9F%E8%AE%A1%E4%BA%8C%E5%8F%89%E6%A0%91%E4%B8%AD%E5%A5%BD%E8%8A%82%E7%82%B9%E7%9A%84%E6%95%B0%E7%9B%AE/用 DFS 维护路径上的当前最大值，统计二叉树中的好节点数目。https://yosgi.github.io/zh/post/1325-%E5%88%A0%E9%99%A4%E7%BB%99%E5%AE%9A%E5%80%BC%E7%9A%84%E5%8F%B6%E5%AD%90%E8%8A%82%E7%82%B9/Wed, 17 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/1325-%E5%88%A0%E9%99%A4%E7%BB%99%E5%AE%9A%E5%80%BC%E7%9A%84%E5%8F%B6%E5%AD%90%E8%8A%82%E7%82%B9/用后序遍历配合虚拟根节点，删除值为目标值的叶子节点。https://yosgi.github.io/zh/post/1022-%E4%BB%8E%E6%A0%B9%E5%88%B0%E5%8F%B6%E7%9A%84%E4%BA%8C%E8%BF%9B%E5%88%B6%E6%95%B0%E4%B9%8B%E5%92%8C/Wed, 17 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/1022-%E4%BB%8E%E6%A0%B9%E5%88%B0%E5%8F%B6%E7%9A%84%E4%BA%8C%E8%BF%9B%E5%88%B6%E6%95%B0%E4%B9%8B%E5%92%8C/自顶向下前序遍历，累计从根到叶的二进制路径并求和。https://yosgi.github.io/zh/post/%E9%9D%A2%E8%AF%95%E9%A2%98-04-12-%E6%B1%82%E5%92%8C%E8%B7%AF%E5%BE%84/Tue, 16 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/%E9%9D%A2%E8%AF%95%E9%A2%98-04-12-%E6%B1%82%E5%92%8C%E8%B7%AF%E5%BE%84/用外层递归遍历节点、内层递归计算路径，统计和为目标值的路径数。https://yosgi.github.io/zh/post/563-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%9D%A1%E5%BA%A6/Tue, 16 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/563-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%9D%A1%E5%BA%A6/用返回子树和的递归计算二叉树的总坡度。https://yosgi.github.io/zh/post/129-%E6%B1%82%E6%A0%B9%E8%8A%82%E7%82%B9%E5%88%B0%E5%8F%B6%E8%8A%82%E7%82%B9%E6%95%B0%E5%AD%97%E4%B9%8B%E5%92%8C/Tue, 16 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/129-%E6%B1%82%E6%A0%B9%E8%8A%82%E7%82%B9%E5%88%B0%E5%8F%B6%E8%8A%82%E7%82%B9%E6%95%B0%E5%AD%97%E4%B9%8B%E5%92%8C/自顶向下前序 DFS，沿路径携带累计值，求所有根到叶数字之和。https://yosgi.github.io/zh/post/124-%E4%BA%8C%E5%8F%89%E6%A0%91%E4%B8%AD%E7%9A%84%E6%9C%80%E5%A4%A7%E8%B7%AF%E5%BE%84%E5%92%8C/Mon, 15 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/124-%E4%BA%8C%E5%8F%89%E6%A0%91%E4%B8%AD%E7%9A%84%E6%9C%80%E5%A4%A7%E8%B7%AF%E5%BE%84%E5%92%8C/用递归返回每个节点向下的最大贡献，求二叉树的最大路径和。https://yosgi.github.io/zh/post/99-%E6%81%A2%E5%A4%8D%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/Sat, 13 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/99-%E6%81%A2%E5%A4%8D%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/利用中序遍历的递增性质定位被交换的两个节点，恢复二叉搜索树。https://yosgi.github.io/zh/post/98-%E9%AA%8C%E8%AF%81%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/Sat, 13 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/98-%E9%AA%8C%E8%AF%81%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/利用二叉搜索树中序遍历递增的性质来验证其合法性。https://yosgi.github.io/zh/post/662-%E4%BA%8C%E5%8F%89%E6%A0%91%E6%9C%80%E5%A4%A7%E5%AE%BD%E5%BA%A6/Sat, 13 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/662-%E4%BA%8C%E5%8F%89%E6%A0%91%E6%9C%80%E5%A4%A7%E5%AE%BD%E5%BA%A6/用 BFS 并为每个节点记录层内位置下标来计算二叉树的最大宽度。https://yosgi.github.io/zh/post/222-%E5%AE%8C%E5%85%A8%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E8%8A%82%E7%82%B9%E4%B8%AA%E6%95%B0/Sat, 13 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/222-%E5%AE%8C%E5%85%A8%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E8%8A%82%E7%82%B9%E4%B8%AA%E6%95%B0/利用完全二叉树左右子树深度的性质统计节点数，避免逐个 DFS。https://yosgi.github.io/zh/post/669-%E4%BF%AE%E5%89%AA%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/Thu, 11 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/669-%E4%BF%AE%E5%89%AA%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/利用二叉搜索树的边界性质，递归进入正确分支修剪到给定区间。https://yosgi.github.io/zh/post/450-%E5%88%A0%E9%99%A4%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91%E4%B8%AD%E7%9A%84%E8%8A%82%E7%82%B9/Thu, 11 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/450-%E5%88%A0%E9%99%A4%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91%E4%B8%AD%E7%9A%84%E8%8A%82%E7%82%B9/先按二叉搜索树性质定位节点，再分三种情况处理删除。https://yosgi.github.io/zh/post/116-%E5%A1%AB%E5%85%85%E6%AF%8F%E4%B8%AA%E8%8A%82%E7%82%B9%E7%9A%84%E4%B8%8B%E4%B8%80%E4%B8%AA%E5%8F%B3%E4%BE%A7%E8%8A%82%E7%82%B9%E6%8C%87%E9%92%88/Wed, 10 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/116-%E5%A1%AB%E5%85%85%E6%AF%8F%E4%B8%AA%E8%8A%82%E7%82%B9%E7%9A%84%E4%B8%8B%E4%B8%80%E4%B8%AA%E5%8F%B3%E4%BE%A7%E8%8A%82%E7%82%B9%E6%8C%87%E9%92%88/逐层把每个节点连到右邻居，利用上一层已有的 next 指针达到常数空间。https://yosgi.github.io/zh/post/1008-%E5%89%8D%E5%BA%8F%E9%81%8D%E5%8E%86%E6%9E%84%E9%80%A0%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/Wed, 10 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/1008-%E5%89%8D%E5%BA%8F%E9%81%8D%E5%8E%86%E6%9E%84%E9%80%A0%E4%BA%8C%E5%8F%89%E6%90%9C%E7%B4%A2%E6%A0%91/通过递归依次插入，从前序序列重建二叉搜索树。https://yosgi.github.io/zh/post/894-%E6%89%80%E6%9C%89%E5%8F%AF%E8%83%BD%E7%9A%84%E6%BB%A1%E4%BA%8C%E5%8F%89%E6%A0%91/Sun, 07 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/894-%E6%89%80%E6%9C%89%E5%8F%AF%E8%83%BD%E7%9A%84%E6%BB%A1%E4%BA%8C%E5%8F%89%E6%A0%91/用递归（动态规划）组合左右子树，生成所有可能的满二叉树。https://yosgi.github.io/zh/post/297-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%BA%8F%E5%88%97%E5%8C%96%E4%B8%8E%E5%8F%8D%E5%BA%8F%E5%88%97%E5%8C%96/Thu, 04 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/297-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%BA%8F%E5%88%97%E5%8C%96%E4%B8%8E%E5%8F%8D%E5%BA%8F%E5%88%97%E5%8C%96/用 BFS 序列化二叉树，并借助父子节点下标关系反序列化。https://yosgi.github.io/zh/post/1372-%E4%BA%8C%E5%8F%89%E6%A0%91%E4%B8%AD%E7%9A%84%E6%9C%80%E9%95%BF%E4%BA%A4%E9%94%99%E8%B7%AF%E5%BE%84/Mon, 01 Mar 2021 00:00:00 +1300https://yosgi.github.io/zh/post/1372-%E4%BA%8C%E5%8F%89%E6%A0%91%E4%B8%AD%E7%9A%84%E6%9C%80%E9%95%BF%E4%BA%A4%E9%94%99%E8%B7%AF%E5%BE%84/用 DFS 记录方向与长度求二叉树中最长的交错路径，并处理边界情况。https://yosgi.github.io/zh/post/%E5%85%B3%E4%BA%8E%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E6%80%BB%E7%BB%93/Sun, 28 Feb 2021 00:00:00 +1300https://yosgi.github.io/zh/post/%E5%85%B3%E4%BA%8E%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E6%80%BB%E7%BB%93/二叉树遍历总结：为什么 DFS 用栈、BFS 用队列，并给出可复用的前中后序与层序模板。https://yosgi.github.io/zh/post/102-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%B1%82%E5%BA%8F%E9%81%8D%E5%8E%86/Sun, 28 Feb 2021 00:00:00 +1300https://yosgi.github.io/zh/post/102-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%B1%82%E5%BA%8F%E9%81%8D%E5%8E%86/二叉树层序遍历（BFS），用 null 标记每层结束的迭代与递归两种写法。https://yosgi.github.io/zh/post/%E5%8F%8C%E8%89%B2%E6%A0%87%E8%AE%B0%E6%B3%95/Sat, 27 Feb 2021 00:00:00 +1300https://yosgi.github.io/zh/post/%E5%8F%8C%E8%89%B2%E6%A0%87%E8%AE%B0%E6%B3%95/借鉴垃圾回收的颜色标记法，用统一模板迭代实现二叉树前中后序遍历。https://yosgi.github.io/zh/post/145-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%90%8E%E5%BA%8F%E9%81%8D%E5%8E%86/Fri, 26 Feb 2021 00:00:00 +1300https://yosgi.github.io/zh/post/145-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%90%8E%E5%BA%8F%E9%81%8D%E5%8E%86/二叉树后序遍历的递归写法与借助栈的迭代写法。https://yosgi.github.io/zh/post/94-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E4%B8%AD%E5%BA%8F%E9%81%8D%E5%8E%86/Thu, 25 Feb 2021 00:00:00 +1300https://yosgi.github.io/zh/post/94-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E4%B8%AD%E5%BA%8F%E9%81%8D%E5%8E%86/二叉树中序遍历的递归写法与借助显式栈的迭代写法。https://yosgi.github.io/zh/post/144-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%89%8D%E5%BA%8F%E9%81%8D%E5%8E%86/Thu, 25 Feb 2021 00:00:00 +1300https://yosgi.github.io/zh/post/144-%E4%BA%8C%E5%8F%89%E6%A0%91%E7%9A%84%E5%89%8D%E5%BA%8F%E9%81%8D%E5%8E%86/二叉树前序遍历，借助显式栈的迭代实现。https://yosgi.github.io/zh/post/105-%E4%BB%8E%E5%89%8D%E5%BA%8F%E9%81%8D%E5%8E%86%E4%B8%8E%E4%B8%AD%E5%BA%8F%E9%81%8D%E5%8E%86%E5%BA%8F%E5%88%97%E6%9E%84%E9%80%A0%E4%BA%8C%E5%8F%89%E6%A0%91-1/Wed, 27 Jan 2021 00:00:00 +1300https://yosgi.github.io/zh/post/105-%E4%BB%8E%E5%89%8D%E5%BA%8F%E9%81%8D%E5%8E%86%E4%B8%8E%E4%B8%AD%E5%BA%8F%E9%81%8D%E5%8E%86%E5%BA%8F%E5%88%97%E6%9E%84%E9%80%A0%E4%BA%8C%E5%8F%89%E6%A0%91-1/根据前序定位根、中序切分左右子树，递归重建二叉树。