732. 我的日程安排表 III 实现一个 MyCalendar 类来存放你的日程安排,你可以一直添加新的日程安排. MyCalendar 有一个 book(int start, int end)方法.它意味着在start到end时间内增加一个日程安排,注意,这里的时间是半开区间,即 [start, end), 实数 x 的范围为, start <= x < end. 当 K 个日程安排有一些时间上的交叉时(例如K个日程安排都在同一时间内),就会产生 K 次预订. 每次调用 MyCalenda…
Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. Ensure that numbers within the set are sorted in ascending order. Example 1…
Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation. For example: Given "aacecaaa", return "aaacecaaa&qu…
Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same le…
Design a data structure that supports the following two operations: void addWord(word)bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter.…
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 first take course 1, which is expressed as a pair: [0,1] Given the total number of courses and a l…
Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by…
Say 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 at most k transactions. 解题思路: https://leetcode.com/discuss/18330/is-it-best-solution-with-o-n-o-1…
