csg3140100993的博客

142.Linked List Cycle IIMedium1883150FavoriteShareGiven a linked list, return the node where the cycle begins. If there is no cycle, returnnull.To represent a cycle in the given linked li...

141.Linked List CycleEasy1969284FavoriteShareGiven a linked list, determine if it has a cycle in it.To represent a cycle in the given linked list, we use an integerposwhich represents th...

139.Word BreakMedium2987164FavoriteShareGiven anon-emptystringsand a dictionarywordDictcontaining a list ofnon-emptywords, determine ifscan be segmented into a space-separated sequ...

138.Copy List with Random PointerMedium2165531FavoriteShareA linked list is given such that each node contains an additional random pointer which could point to any node in the list or null....

136.Single NumberEasy3087121FavoriteShareGiven anon-emptyarray of integers, every element appearstwiceexcept for one. Find that single one.Note:Your algorithm should have a linear runti...

128.Longest Consecutive SequenceHard2363134FavoriteShareGiven an unsorted array of integers, find the length of the longest consecutive elements sequence.Your algorithm should run in O(n) ...

124.Binary Tree Maximum Path SumHard2263182FavoriteShareGiven anon-emptybinary tree, find the maximum path sum.For this problem, a path is defined as any sequence of nodes from some star...

114.Flatten Binary Tree to Linked ListMedium1926248FavoriteShareGiven a binary tree, flatten it to a linked list in-place.For example, given the following tree: 1 / \ 2 5 / \...

105.Construct Binary Tree from Preorder and Inorder TraversalMedium225462FavoriteShareGiven preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that du...

104.Maximum Depth of Binary TreeEasy170062FavoriteShareGiven a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down t...

102.Binary Tree Level Order TraversalMedium195352FavoriteShareGiven a binary tree, return thelevel ordertraversal of its nodes' values. (ie, from left to right, level by level).For examp...

101.Symmetric TreeEasy286066FavoriteShareGiven a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree[1,2,2,3,4,4,3]is symm...

85.Maximal RectangleHard188155FavoriteShareGiven a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area.Example:Input:[ ["1","...

84.Largest Rectangle in HistogramHard249564FavoriteShareGivennnon-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest recta...

79.Word SearchMedium2421130FavoriteShareGiven a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, where "adja...

78.SubsetsMedium254762FavoriteShareGiven a set ofdistinctintegers,nums, return all possible subsets (the power set).Note:The solution set must not contain duplicate subsets.Example:...

75.Sort ColorsMedium2145181FavoriteShareGiven an array withnobjects colored red, white or blue, sort themin-placeso that objects of the same color are adjacent, with the colors in the or...

72.Edit DistanceHard267741FavoriteShareGiven two wordsword1andword2, find the minimum number of operations required to convertword1toword2.You have the following 3 operations permitt...

70.Climbing StairsEasy286098FavoriteShareYou are climbing a stair case. It takesnsteps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you ...

64.Minimum Path SumMedium175445FavoriteShareGiven amxngrid filled with non-negative numbers, find a path from top left to bottom right whichminimizesthe sum of all numbers along its pa...

62.Unique PathsMedium2049151FavoriteShareA robot is located at the top-left corner of amxngrid (marked 'Start' in the diagram below).The robot can only move either down or right at any...

56.Merge IntervalsMedium2757219FavoriteShareGiven a collection of intervals, merge all overlapping intervals.Example 1:Input: [[1,3],[2,6],[8,10],[15,18]]Output: [[1,6],[8,10],[15,18]]...

55.Jump GameMedium2562244FavoriteShareGiven an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximu...

53.Maximum SubarrayEasy5417226FavoriteShareGiven an integer arraynums, find the contiguous subarray(containing at least one number) which has the largest sum and return its sum.Example:...

49.Group AnagramsMedium2177134FavoriteShareGiven an array of strings, group anagrams together.Example:Input: ["eat", "tea", "tan", "ate", "nat", "bat"],Output:[ ["ate","eat","tea"],...

48.Rotate ImageMedium2022179FavoriteShareYou are given annxn2D matrix representing an image.Rotate the image by 90 degrees (clockwise).Note:You have to rotate the imagein-place, w...

46.PermutationsMedium261784FavoriteShareGiven a collection ofdistinctintegers, return all possible permutations.Example:Input: [1,2,3]Output:[ [1,2,3], [1,3,2], [2,1,3], [2,...

100.Same TreeEasy138245FavoriteShareGiven two binary trees, write a function to check if they are the same or not.Two binary trees are considered the same if they are structurally identica...

99.Recover Binary Search TreeHard99658FavoriteShareTwo elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Example 1:Input: [...

98.Validate Binary Search TreeMedium2566373FavoriteShareGiven a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a ...

95.Unique Binary Search Trees IIMedium1552129FavoriteShareGiven an integern, generate all structurally uniqueBST's(binary search trees) that store values 1 ...n.Example:Input: 3Out...

94.Binary Tree Inorder TraversalMedium210093FavoriteShareGiven a binary tree, return theinordertraversal of its nodes' values.Example:Input: [1,null,2,3] 1 \ 2 / 3...

42.Trapping Rain WaterHard477683FavoriteShareGivennnon-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after rai...

41.First Missing PositiveHard2244664FavoriteShareGiven an unsorted integer array, find the smallest missingpositive integer.Example 1:Input: [1,2,0]Output: 3Example 2:Input: [3,...

39.Combination SumMedium260179FavoriteShareGiven asetof candidate numbers (candidates)(without duplicates)and a target number (target), find all unique combinations incandidateswhere t...

34.Find First and Last Position of Element in Sorted ArrayMedium2152100FavoriteShareGiven an array of integersnumssorted in ascending order, find the starting and ending position of a give...

33.Search in Rotated Sorted ArrayMedium3137371FavoriteShareSuppose 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...

32. Longest Valid ParenthesesHardGiven a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.Example 1:Input: "(()"...

31. Next PermutationMediumImplement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangement is not possible, it must rear...

23. Merge k Sorted ListsHardMerge 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]...