Yolanda Jia

Given a linked list, remove the n-th node from the end of list and return its head.Example:Given linked list: 1->2->3->4->5, and n = 2.After removing the second node from the end, the li...

Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:The solution set must not contain ...

Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three integers. You may assume that each input would ...

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a solution set is:[ "((()))", "(()())", "(())()", "()(())", "...

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.An input string is valid if:Open brackets must be closed by the same type of brack...

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.Example:Input: 1->2->4, 1->3->4Output: 1->1...

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.Example:Input:[  1->4->5,  1->3->4,  2->6]Output: 1->1->2->3->4-...

Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length.Do not allocate extra space for another array, you must do this by modifyi...

Given an array nums and a value val, remove all instances of that value in-place and return the new length.Do not allocate extra space for another array, you must do this by modifying the input arra...

Implement strStr().Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.Example 1:Input: haystack = "hello", needle = "ll"Output: 2Example...

Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator.Return the quotient after dividing dividend by divisor.The integer division sho...

You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) in s that is a concatenation of each word in words exactly once and wi...

Example:Given 1->2->3->4, you should return the list as 2->1->4->3.Note:Your algorithm should use only constant extra space. You may not modify the values in the list's nodes...

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.k is a positive integer and is less than or equal to the length of the linked list. If the number of ...

Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangement is not possible, it must rearrange it as the lowest possible o...

Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.Example 1:Input: "(()"Output: 2Explanation: The longest valid...

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.Symbol ValueI 1V 5X 10L 50C 100D 5...

Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of tar...

【题目】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 check. Since each version is developed ba

【题目】Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).Find the minimum element.You may

【题目】Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:Integers in each row are sorted from left to right.The first integer

There are two sorted arrays nums1 and nums2 of size m and n respectively.Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).Example 1:nums1 = [1, 3]nums2...

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.Example:Input: "babad"Output: "bab"Note: "aba" is also a valid answer. Example:I...

The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)P A H NA P L S I I G...

Given a 32-bit signed integer, reverse digits of an integer.Example 1:Input: 123Output: 321Example 2:Input: -123Output: -321Example 3:Input: 120Output: 21Note:Assume we are dealing with an envi...

Determine whether an integer is a palindrome. Do this without extra space.思路：edge case:x < 0 ==> falsex == 0 ==> truex = 10, 100,... ==> false解法一：1. 如果input x是负数，直接返回false2. 考虑overflow情况，因...

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return i...

Given a string, find the length of the longest substring without repeating characters.Examples:Given "abcabcbb", the answer is "abc", which the length is 3.Given "bbbbb", the answer is "b", with the l...

Implement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases....

Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two ...

Given an input string (s) and a pattern (p), implement regular expression matching with support for '.' and '*'.'.' Matches any single character.'*' Matches zero or more of the preceding element.The...

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.Symbol ValueI 1V 5X 10L 50C 100D 5...

Write a function to find the longest common prefix string amongst an array of strings.If there is no common prefix, return an empty string "".Example 1:Input: ["flower","flow","flight"]Output: "fl"E...

Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent.A mapping of digit to letters (just like on the telephone buttons) is given...

Given a binary tree, return the inorder traversal of its nodes' values.Example:Input: [1,null,2,3] 1 \ 2 / 3Output: [1,3,2]Follow up: Recursive solution is trivial, could y...