Leetcode - 随笔分类(第3页) - Beserious

leetcode 543. Diameter of Binary Tree

摘要：Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path betwe 阅读全文

posted @ 2018-03-01 09:28 Beserious 阅读(93) 评论(0) 推荐(0) 编辑

leetcode 551. Student Attendance Record I

摘要：You are given a string representing an attendance record for a student. The record only contains the following three characters: 'A' : Absent. 'L' : L 阅读全文

posted @ 2018-03-01 09:14 Beserious 阅读(116) 评论(0) 推荐(0) 编辑

leetcode 563. Binary Tree Tilt

摘要：Given a binary tree, return the tilt of the whole tree. The tilt of a tree node is defined as the absolute difference between the sum of all left subt 阅读全文

posted @ 2018-03-01 09:12 Beserious 阅读(101) 评论(0) 推荐(0) 编辑

leetcode 598. Range Addition II

摘要：Given an m n matrix M initialized with all 0's and several update operations. Operations are represented by a 2D array, and each operation is represen 阅读全文

posted @ 2018-03-01 09:09 Beserious 阅读(99) 评论(0) 推荐(0) 编辑

leetcode 599. Minimum Index Sum of Two Lists

摘要：Suppose Andy and Doris want to choose a restaurant for dinner, and they both have a list of favorite restaurants represented by strings. You need to h 阅读全文

posted @ 2018-03-01 09:05 Beserious 阅读(93) 评论(0) 推荐(0) 编辑

leetcode 606. Construct String from Binary Tree

摘要：You need to construct a string consists of parenthesis and integers from a binary tree with the preorder traversing way. The null node needs to be rep 阅读全文

posted @ 2018-03-01 08:59 Beserious 阅读(99) 评论(0) 推荐(0) 编辑

leetcode 690. Employee Importance

摘要：You are given a data structure of employee information, which includes the employee's unique id, his importance value and his direct subordinates' id. 阅读全文

posted @ 2018-03-01 08:53 Beserious 阅读(112) 评论(0) 推荐(0) 编辑

leetcode 404. Sum of Left Leaves

摘要：Find the sum of all left leaves in a given binary tree. 思路：在递归的时候访问左右节点记录一下，比如做节点标记1，右节点标2，那么当遍历到叶子节点的时候，我们只加标记为1的叶子节点的值。阅读全文

posted @ 2018-02-28 19:39 Beserious 阅读(51) 评论(0) 推荐(0) 编辑

leetcode 263. Ugly Number

摘要：Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For exa 阅读全文

posted @ 2018-02-28 19:34 Beserious 阅读(83) 评论(0) 推荐(0) 编辑

leetcode 278. First Bad Version

摘要：You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality c 阅读全文

posted @ 2018-02-28 19:33 Beserious 阅读(91) 评论(0) 推荐(0) 编辑

leetcode 303. Range Sum Query - Immutable

摘要：Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. 前缀和思想。如果修改的次数比较多，那么就可以用线段树了, class NumArray { pu 阅读全文

posted @ 2018-02-28 19:29 Beserious 阅读(84) 评论(0) 推荐(0) 编辑

leetcode 326. Power of Three

摘要：Given an integer, write a function to determine if it is a power of three. 判断一个数，是不是3的n次幂。直接换底公式求解阅读全文

posted @ 2018-02-28 19:22 Beserious 阅读(86) 评论(0) 推荐(0) 编辑

leetcode 350. Intersection of Two Arrays II

摘要：Given two arrays, write a function to compute their intersection. Example: Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2]. Note: Each eleme 阅读全文

posted @ 2018-02-28 19:07 Beserious 阅读(97) 评论(0) 推荐(0) 编辑

leetcode 371. Sum of Two Integers

摘要：Calculate the sum of two integers a and b, but you are not allowed to use the operator + and . Example: Given a = 1 and b = 2, return 3. 不用加减法进行求和运算。阅读全文

posted @ 2018-02-28 19:03 Beserious 阅读(104) 评论(0) 推荐(0) 编辑

leetcode 237. Delete Node in a Linked List

摘要：Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 2 3 4 and y 阅读全文

posted @ 2018-02-28 18:25 Beserious 阅读(82) 评论(0) 推荐(0) 编辑

leetcode 367. Valid Perfect Square

摘要：Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built in library functio 阅读全文

posted @ 2018-02-28 18:23 Beserious 阅读(123) 评论(0) 推荐(0) 编辑

leetcode 234. Palindrome Linked List

摘要：Given a singly linked list, determine if it is a palindrome. Follow up: Could you do it in O(n) time and O(1) space? 判断一个链表是不是回文的。思路：遍历节点得到总数tot，然后反转阅读全文

posted @ 2018-02-28 18:21 Beserious 阅读(105) 评论(0) 推荐(0) 编辑

leetcode 232. Implement Queue using Stacks

摘要：Implement the following operations of a queue using stacks. push(x) Push element x to the back of queue. pop() Removes the element from in front of qu 阅读全文

posted @ 2018-02-28 18:16 Beserious 阅读(131) 评论(0) 推荐(0) 编辑

leetcode 225. Implement Stack using Queues

摘要：Implement the following operations of a stack using queues. push(x) Push element x onto stack. pop() Removes the element on top of the stack. top() Ge 阅读全文

posted @ 2018-02-28 18:14 Beserious 阅读(129) 评论(0) 推荐(0) 编辑

leetcode 206. Reverse Linked List

摘要：Reverse a singly linked list. 思路：递归，每次保存一下上一个节点用来构造反转后的链表。非递归，需要多记录两个值. 阅读全文

posted @ 2018-02-28 18:09 Beserious 阅读(90) 评论(0) 推荐(0) 编辑

随笔分类 - Leetcode