LawFile的博客

题目描述：Given an array of integersarrand an integertarget.You have to findtwo non-overlapping sub-arraysofarreach with sum equaltarget. There can be multiple answers so you have to find an answer where the sum of the lengths of the two sub-arrays ...

题目描述：There are several cardsarranged in a row, and each card has an associated number of pointsThe points are given in the integer arraycardPoints.In one step, you can take one card from the beginning or from the end of the row. You have to take exa...

题目描述：You have a lock in front of you with 4 circular wheels. Each wheel has 10 slots:'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'. The wheels can rotate freely and wrap around: for example we can turn'9'to be'0', or'0'to be'9'. Each move consi...

题目描述：Given anarray of integersnumsand anintegerlimit, return the size of the longestnon-emptysubarray such that the absolute difference between any two elements of this subarray is less than or equal tolimit.Example 1:Input: nums = [8,2,4,7]...

题目描述：Given two sequencespushedandpoppedwith distinct values,returntrueif and only if this could have been the result of a sequence of push and pop operations on an initially empty stack.Example 1:Input: pushed = [1,2,3,4,5], popped = [4,5,3,2...

题目描述：Given a binary tree, flatten it to a linked list in-place.For example,Given 1 / \ 2 5 / \ \ 3 4 6The flattened tree should look like

题目描述：Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.Above is a histogram where

题目描述：Given 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 "adjacent" cells are those horizontally or

题目描述：Given a set of distinct integers, nums, return all possible subsets.Note: The solution set must not contain duplicate subsets.For example,If nums = [1,2,3], a solution is:[

题目描述：Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue.Here, we will use

题目描述：Given an array and a value, 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 in place with constant

题目描述：Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)You have the following 3 operations permitted

题目描述：Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area.For example, given the following matrix:1 0 1 0 01 0 1 1 11 1 1

题目描述：Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.这种题型显然应该采用递归的方法，从任意一个节点开始

题目描述：Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.这道题为easy难度，所以对时间复杂度要求不高，可以直接用暴力的方法解决，即先在haystack中匹配needle的第

题目描述：Given preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not exist in the tree.根据前序遍历和中序遍历构造二叉树。还是利用递归来解决，前序遍历的第一个元素即为二叉树的根节点

题目描述：Given a collection of intervals, merge all overlapping intervals.For example,Given [1,3],[2,6],[8,10],[15,18],return [1,6],[8,10],[15,18].要将区间合并，即找出相交的区间范围，然后合并。思想方法就是遍历区间数组，并查找已经

题目描述：Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n).For example,S = "ADOBECODEBANC"T = "ABC"Minimum win

题目描述：A message containing letters from A-Z is being encoded to numbers using the following mapping:'A' -> 1'B' -> 2...'Z' -> 26Given an encoded message containing digits, determine the tot

题目描述：We are given a matrix withRrows andCcolumns has cells with integer coordinates(r, c), where0 <= r < Rand0 <= c < C.Additionally, we are given a cell in that matrix with co...

题目描述：Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximum jump length at that position.

题目描述：Find the contiguous subarray within an array (containing at least one number) which has the largest sum.For example, given the array [-2,1,-3,4,-1,2,1,-5,4],the contiguous subarray [4

题目描述：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.此题可以直接模拟归并排序的步骤，但是要小心指针为空的情况。/** * Defini

题目描述：Given an array S of n integers, are there elements a,b, c, and d in S such that a + b +c + d = target? Find all unique quadruplets in the array which gives the sum of target.Note: The s

题目描述：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:[ "((()))", "(()())", "(())()",

题目描述： Given a linked list, remove the nth node from the end of list and return its head.For example, Given linked list: 1-&gt;2-&gt;3-&gt;4-&gt;5, and n = 2. After removing the second n...

题目描述：Given an array S of n integers, are there elements a,b, c in S 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 c

题目描述：Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.For "(()", the longest valid parentheses substring

题目描述：Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.本题较简单，我采用的方法是从字符串第一位开始进行识别并确定其代表的数值大小后加入integer，根据罗马数字表示规则，进行分类讨论，识别完后将字符删去。c

题目描述：Implement regular expression matching with support for '.' and '*'.'.' Matches any single character.'*' Matches zero or more of the preceding element.The matching should cover the enti

题目描述：Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity这道题可以利用mergeTwoLists来做，一种方法是将k个链表一个一个地归并，即需要k步。随着归并的次数越多，已经归并的链表会越来越长，所以效率比较差。在这道题的最后一个测试案例中

题目描述：Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only consta

题目描述：Given an array of strings, group anagrams together.For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"], Return:[ ["ate", "eat","tea"], ["nat","tan"], ["bat"]]找出字

题目描述：Given a collection of distinct numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2

题目描述：Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.For example, Given [0,1,0,2,1,0,1

题目描述：Given a set of candidate numbers (C) (without duplicates) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.The same repeated number may be chosen f...

题目描述：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).You are given a target value to sear

题目描述：Given a sorted array, 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 in

题目描述：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 t

题目描述：Reverse a singly linked list.click to show more hints.Hint:A linked list can be reversed either iteratively or recursively. Could you implement both?实现链表的翻转，而且题目提示可以尝试迭代和递归两种方