DaVinciL的博客

给你一个以字符串形式表述的 布尔表达式（boolean） expression，返回该式的运算结果。有效的表达式需遵循以下约定：“t”，运算结果为 True“f”，运算结果为 False“!(expr)”，运算过程为对内部表达式 expr 进行逻辑 非的运算（NOT）“&(expr1,expr2,…)”，运算过程为对 2 个或以上内部表达式 expr1, expr2, … 进行逻辑 与的运算（AND）“|(expr1,expr2,…)”，运算过程为对 2 个或以上内部表达式 expr1

  You are given an array coordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these points make a straight line in the XY plane.Example 1:Input: coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]Output: tru

ProblemGiven an array A of integers, return true if and only if we can partition the array into three non-empty parts with equal sums.Formally, we can partition the array if we can find indexes i+1 ...

ProblemThere are 2N people a company is planning to interview. The cost of flying the i-th person to city A is costs[i][0], and the cost of flying the i-th person to city B is costs[i][1].Return the...

ProblemYour task is to calculate aba^bab mod 1337 where a is a positive integer and b is an extremely large positive integer given in the form of an array.Example 1:Input: a = 2, b = [3]Output: 8...

ProblemWinter is coming! Your first job during the contest is to design a standard heater with fixed warm radius to warm all the houses.Now, you are given positions of houses and heaters on a horizo...

ProblemFind the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.Example 1:Input: [3,2,1,5,6,4] and k = 2Output:...

ProblemGiven a non-empty array of integers, every element appears three times except for one, which appears exactly once. Find that single one.Note:Your algorithm should have a linear runtime comp...

ProblemGiven the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on.Return the smallest level X such that the sum of all the values of nodes at level X is m...

ProblemThere are N network nodes, labelled 1 to N.Given times, a list of travel times as directed edges times[i] = (u, v, w), where u is the source node, v is the target node, and w is the time it t...

ProblemWe are given a binary tree (with root node root), a target node, and an integer value K.Return a list of the values of all nodes that have a distance K from the target node. The answer can b...

ProblemIn this problem, a tree is an undirected graph that is connected and has no cycles.The given input is a graph that started as a tree with N nodes (with distinct values 1, 2, …, N), with one a...

ProblemGiven a matrix of M x N elements (M rows, N columns), return all elements of the matrix in diagonal order as shown in the below image.Example:Input:[[ 1, 2, 3 ],[ 4, 5, 6 ],[ 7, 8, 9 ]...

ProblemSay you have an array for which the ith element is the price of a given stock on day i.Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, b...

ProblemYour are given an array of integers prices, for which the i-th element is the price of a given stock on day i; and a non-negative integer fee representing a transaction fee.You may complete a...

ProblemSay you have an array for which the ithi^{th}ith element is the price of a given stock on day i.If you were only permitted to complete at most one transaction (i.e., buy one and sell one shar...

ProblemA conveyor belt has packages that must be shipped from one port to another within D days.The i-th package on the conveyor belt has a weight of weights[i]. Each day, we load the ship with pac...

ProblemGiven a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.Example 1:Input: 1->2->3->3->4->4->5Output:...

ProblemYou are given a doubly linked list which in addition to the next and previous pointers, it could have a child pointer, which may or may not point to a separate doubly linked list. These child ...

problemGiven a binary treestruct Node {int val;Node *left;Node *right;Node *next;}Populate each next pointer to point to its next right node. If there is no next right node, the next pointer...

ProblemDetermine if a 9x9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules:Each row must contain the digits 1-9 without repetition.Each column mus...

ProblemGiven 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 inpu...

ProblemGiven a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place.Example 1:Input:[[1,1,1],[1,0,1],[1,1,1]]Output:[[1,0,1],[0,0,0],[1,0,1]]Example 2:...

ProblemIn an infinite binary tree where every node has two children, the nodes are labelled in row order.In the odd numbered rows (ie., the first, third, fifth,…), the labelling is left to right, wh...

ProblemYou have ddd dice, and each die has fff faces numbered 1, 2, …, f.Return the number of possible ways (out of fd total ways) modulo 10^9 + 7 to roll the dice so the sum of the face up numbers ...

ProblemGiven 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)...

ProblemWe have a set of items: the i-th item has value values[i] and label labels[i].Then, we choose a subset S of these items, such that:|S| <= num_wantedFor every label L, the number of ite...

ProblemIn a group of N people (labelled 0, 1, 2, …, N-1), each person has different amounts of money, and different levels of quietness.For convenience, we’ll call the person with label x, simply “p...

ProblemGiven two strings text1 and text2, return the length of their longest common subsequence.A subsequence of a string is a new string generated from the original string with some characters(can ...

ProblemGiven an N x N grid containing only values 0 and 1, where 0 represents water and 1 represents land, find a water cell such that its distance to the nearest land cell is maximized and return th...

ProblemYou are driving a vehicle that has capacity empty seats initially available for passengers. The vehicle only drives east (ie. it cannot turn around and drive west.)Given a list of trips, tri...

ProblemGiven a non-empty list of words, return the k most frequent elements.Your answer should be sorted by frequency from highest to lowest. If two words have the same frequency, then the word with...

ProblemGiven an encoded string, return its decoded string.The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. Note that k ...

ProblemIn an election, the i-th vote was cast for persons[i] at time times[i].Now, we would like to implement the following query function: TopVotedCandidate.q(int t) will return the number of the p...

ProblemThere 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 first take course 1, which is expressed as...

ProblemGiven a set of distinct integers, nums, return all possible subsets (the power set).Note: The solution set must not contain duplicate subsets.Example:Input: nums = [1,2,3]Output:[[3],[...

ProblemThere 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 first take course 1, which is expressed as...

ProblemYou 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 ...

ProblemWe sampled integers between 0 and 255, and stored the results in an array count: count[k] is the number of integers we sampled equal to k.Return the minimum, maximum, mean, median, and mode ...

ProblemIn a warehouse, there is a row of barcodes, where the i-th barcode is barcodes[i].Rearrange the barcodes so that no two adjacent barcodes are equal. You may return any answer, and it is guar...