随笔分类 - LeetCode
摘要：Implement a trie with insert, search, and startsWith methods. Example: Note: You may assume that all inputs are consist of lowercase letters a-z. All
阅读全文
摘要：There are a total of n courses you have to take, labeled from 0 to n-1. Some courses may have prerequisites, for example to take course 0 you have to
阅读全文
摘要：Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k]
阅读全文
摘要：Given a string s, find the length of the longest substring without repeating characters. Example 1: Input: s = "abcabcbb" Output: 3 Explanation: The a
阅读全文
摘要：Reverse a singly linked list. Example: Follow up: A linked list can be reversed either iteratively or recursively. Could you implement both? 之前做到 Reve
阅读全文
摘要：Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays. The overall run time complexity shou
阅读全文
摘要：Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced to get t. All occurrenc
阅读全文
摘要：Given a string s, return the longest palindromic substring in s. Example 1: Input: s = "babad" Output: "bab" Explanation: "aba" is also a valid answer
阅读全文
摘要：Count the number of prime numbers less than a non-negative number, n. Example 1: Input: n = 10 Output: 4 Explanation: There are 4 prime numbers less t
阅读全文
摘要：Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*' where: '.' Matches any single character.
阅读全文
摘要：You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, hei
阅读全文
摘要：Remove all elements from a linked list of integers that have value val. Example Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6 Return: 1 --> 2
阅读全文
摘要：Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any
阅读全文
摘要：Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive intege
阅读全文
摘要：Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Example 1: Input: n = 3 Output: ["((()))","(()
阅读全文
摘要：Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i
阅读全文
摘要：Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list. k is a positive integer and is less than or
阅读全文
摘要：Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator. The integer division should tru
阅读全文
摘要：Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive. For example, given the range [5,
阅读全文
摘要：A permutation of an array of integers is an arrangement of its members into a sequence or linear order. For example, for arr = [1,2,3], the following
阅读全文
