随笔分类 - leetcode
[Leetcode 111]二叉树的最短深度 BFS/DFS
摘要：题目 给定二叉树，求最短路径包含的节点个数 https://leetcode.com/problems/minimum-depth-of-binary-tree/ Given a binary tree, find its minimum depth. The minimum depth is th
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[Leetcode 108]有序数组转BST二叉搜索树Convert Sorted Array to Binary Search Tree
摘要：题目 https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/ Given an integer array nums where the elements are sorted in ascending or
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[Leetcode 22]生成括号generate parentheses
摘要：题目 给定括号对数n，生成所有可能的标准括号结果* *指不能）（ https://leetcode.com/problems/generate-parentheses/ Given n pairs of parentheses, write a function to generate all co
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[Leetcode 559]N叉树的最大深度Maximum Depth of N-ary Tree DFS/BFS模板
摘要：题目 https://leetcode.com/problems/maximum-depth-of-n-ary-tree/ N叉树的最大深度 Given a n-ary tree, find its maximum depth. The maximum depth is the number of
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[Leetcode 701]二叉搜索树BST中插入元素
摘要：题目 BST二叉搜索树中插入元素 二叉搜索树：左边<root<右边 https://leetcode.com/problems/insert-into-a-binary-search-tree/ You are given the root node of a binary search tree
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[Leetcode 235/236]LCA二叉树最近公共祖先Lowest Common Ancestor of a Binary Tree
摘要：题目 给定二叉树和两个点，求两点的LCA最近公共祖先 Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of L
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[Leetcode 98]判断有效的二叉搜索树Validate Binary Search Tree
摘要：题目 https://leetcode.com/problems/validate-binary-search-tree 判断所给二叉树是否是二叉搜索树 二叉搜索树：其值left<root<right *[2,2,2]这种相等的情况也不是搜索树 Given the root of a binary
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[Leetcode 104]二叉树最大深度Maximum Depth of Binary Tree
摘要：题目 求二叉树的深度，即根节点出发的最长路径上点的个数，即最长路径+1(本身这个点 https://leetcode.com/problems/maximum-depth-of-binary-tree/ Given the root of a binary tree, return its maxi
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[Leetcode 787]中转K站内最便宜机票
摘要：题目 n个城市，想求从src到dist的最廉价机票 有中转站数K的限制，即如果k=5，中转10次机票1000，中转5次机票2000，最后返回2000 There are n cities connected by some number of flights. You are given an ar
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[Leetcode 1631]最少体力消耗的路径Path With Minimum Effort
摘要：题目 https://leetcode.com/problems/path-with-minimum-effort/ 每个节点的height不同，矩阵从左上走到右下，求最小体力消耗 当前点体力消耗：max（来的那个节点的effort，|来的那个节点height-当前节点height|） 总最小体力消
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[Leetcode 451]*Sort Characters By Frequency优先队列
摘要：题目 Given a string s, sort it in decreasing order based on the frequency of the characters. The frequency of a character is the number of times it appe
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[Leetcode 692/347]前K个高频词Top K Frequent Words Element
摘要：题目347 https://leetcode.com/problems/top-k-frequent-elements/ 347简单些，692是其变式，多了一种排序 Given an integer array nums and an integer k, return the k most fre
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[Leetcode 703]流中第K个最大元素Kth Largest Element in a Stream优先队列239
摘要：题目 找到一串数字中的第K大元素 在原数组的基础上，每次会不断插入元素 插入的同时要返回插入后第K大的元素 https://leetcode.com/problems/kth-largest-element-in-a-stream/ Design a class to find the kth la
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[Leetcode 5] 最长回文子串Longest Palindromic Substring
摘要：问题 求最长回文子串，即左右对称 Given a string s, return the longest palindromic substring in s. Example 1: Input: s = "babad" Output: "bab" Note: "aba" is also a va
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[Leetcode 42]雨天积水面积Trapping Rain Water
摘要：题目 下雨天的蓄水量计算 Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after ra
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[Leetcode 1041]机器人围成圈 Robot Bounded In Circle
摘要：题目 机器人从（0,0）出发，初始化向北 三种指令 G当前方向+1步，L左转90度，R右转90度 问指令结束后是否成圆圈（只有可能回原点时才成圈） 返回true/false On an infinite plane, a robot initially stands at (0, 0) and fa
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[Leetcode 138]复制带随机指针的数列Copy List with Random Pointer
摘要：题目 深复制一个list* Node的结构包含next和random（随机指向节点） 区别 深复制 deep copy Node a=New Node(1) Node b=new Node(1) 复制值 浅复制 shallow copy Node a=new Node(1); Node b=a; 复
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[Leetcode 207/210]课程计划Course Schedule I II（BFS）310
摘要：310题目类似，但是数据结构可以选的更简单 恢复内容开始 题目 先修课程和后修课，比如高数离散修完，才能修数据结构 给定numcourse门课程，int[][]的先后计划。int[i][0]为要修的当前课程，int[i][1]为学这门课之前要修的课 207/210都在问：按照int[][]，所有课程
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[Leetcode 103]二叉树zigzag交叉遍历Binary Tree Zigzag Level Order Traversal
摘要：题目 二叉树zigzag遍历 层次遍历：始终左右 zigzag遍历：每层右左左右交替 Given the root of a binary tree, return the zigzag level order traversal of its nodes' values. (i.e., from
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[Leetcode 124]二叉树最大权重路径和 Binary Tree Maximum Path Sum
摘要：题目 与543相似，543是求最长路径，这是最大权重求和（路径不一定最长） A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge con
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