[LeetCode] 930. Binary Subarrays With Sum Given a binary array nums and an integer goal, return the number of non-empty subarrays with a sum goal. A subarray is a contiguous part of the array. Example 1:Input: nums = [1,0,1,0,1], goal 2021-05-05 #leetcode #array #hashmap #java #prefix sum #sliding window
[LeetCode] 1845. Seat Reservation Manager Design a system that manages the reservation state of n seats that are numbered from 1 to n. Implement the SeatManager class: SeatManager(int n) Initializes a SeatManager object that will manage n se 2021-05-02 #leetcode #java #design #heap
[LeetCode] 1244. Design A Leaderboard Design a Leaderboard class, which has 3 functions: addScore(playerId, score): Update the leaderboard by adding score to the given player’s score. If there is no player with such id in the leaderboard, 2021-04-27 #leetcode #hashmap #java #sort #design
[LeetCode] 1838. Frequency of the Most Frequent Element The frequency of an element is the number of times it occurs in an array. You are given an integer array nums and an integer k. In one operation, you can choose an index of nums and increment the elem 2021-04-26 #leetcode #array #greedy #prefix sum #sort #sliding window
[LeetCode] 1670. Design Front Middle Back Queue Design a queue that supports push and pop operations in the front, middle, and back. Implement the FrontMiddleBack class:FrontMiddleBack() Initializes the queue.void pushFront(int val) Adds val to the 2021-04-18 #leetcode #java #design #queue
[LeetCode] 1704. Determine if String Halves Are Alike You are given a string s of even length. Split this string into two halves of equal lengths, and let a be the first half and b be the second half. Two strings are alike if they have the same number of 2021-04-08 #leetcode #two pointer #java #string
[LeetCode] 1749. Maximum Absolute Sum of Any Subarray You are given an integer array nums. The absolute sum of a subarray [numsl, numsl+1, …, numsr-1, numsr] is abs(numsl + numsl+1 + … + numsr-1 + numsr). Return the maximum absolute sum of any (possibly 2021-03-25 #leetcode #array #java #greedy #prefix sum
[LeetCode] 1801. Number of Orders in the Backlog You are given a 2D integer array orders, where each orders[i] = [price, amount, orderType] denotes that amount orders have been placed of type orderType at the price price. The orderTyp is:0 if i 2021-03-22 #leetcode #java #MOD #greedy #heap
[LeetCode] 670. Maximum Swap You are given an integer num. You can swap two digits at most once to get the maximum valued number. Return the maximum valued number you can get. Example 1:Input: num = 2736Output: 7236Explanati 2021-03-18 #leetcode #array #java #greedy #math
[LeetCode] 1481. Least Number of Unique Integers after K Removals Given an array of integers arr and an integer k. Find the least number of unique integers after removing exactly k elements. Example 1:Input: arr = [5,5,4], k = 1Output: 1Explanation: Remove 2021-03-12 #leetcode #array #hashmap #java #greedy #sort #heap