leetcode Guess Number Higher or Lower
We are playing the Guess Game. The game is as follows:
I pick a number from 1 to n. You have to guess which number I picked.
Every time you guess wrong, I’ll tell you whether the number is higher or lower.
You call a pre-defined API
guess(int num)which returns 3 possible results (
123 -1 : My number is lower1 : My number is higher0 : Congrats! You got it!
123 n = 10, I pick 6.Return 6.
leetcode Find K Pairs with Smallest Sums
You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k.
Define a pair (u,v) which consists of one element from the first array and one element from the second array.
Find the k pairs (u1,v1),(u2,v2) …(uk,vk) with the smallest sums.
123456 Given nums1 = [1,7,11], nums2 = [2,4,6], k = 3Return: [1,2],[1,4],[1,6]The first 3 pairs are returned from the sequence:[1,2],[1,4],[1,6],[7,2],[7,4],[11,2],[7,6],[11,4],[11,6]
123456 Given nums1 = [1,1,2], nums2 = [1,2,3], k = 2Return: [1,1],[1,1]The first 2 pairs are returned from the sequence:[1,1],[1,1],[1,2],[2,1],[1,2],[2,2],[1,3],[1,3],[2,3]
123456 Given nums1 = [1,2], nums2 = , k = 3Return: [1,3],[2,3]All possible pairs are returned from the sequence:[1,3],[2,3]
leetcode Super Pow
Your task is to calculate ab mod 1337 where a is a positive integer and b is an extremely large positive integer given in the form of an array.
1234 a = 2b = Result: 8
1234 a = 2b = [1,0]Result: 1024
leetcode Sum of Two Integers
Calculate the sum of two integers a and b, but you are not allowed to use the operator
Given a = 1 and b = 2, return 3.
leetcode Largest Divisible Subset
Given a set of distinct positive integers, find the largest subset such that every pair (Si, Sj) of elements in this subset satisfies: Si % Sj = 0 or Sj% Si = 0.
If there are multiple solutions, return any subset is fine.
123 nums: [1,2,3]Result: [1,2] (of course, [1,3] will also be ok)
123 nums: [1,2,4,8]Result: [1,2,4,8]
leetcode Valid Perfect Square
Given a positive integer num, write a function which returns True if num is a perfect square else False.
Note: Do not use any built-in library function such as
12 Input: 16Returns: True
12 Input: 14Returns: False
leetcode Water and Jug Problem
You are given two jugs with capacities x and y litres. There is an infinite amount of water supply available. You need to determine whether it is possible to measure exactly z litres using these two jugs.
- Fill any of the jugs completely.
- Empty any of the jugs.
- Pour water from one jug into another till the other jug is completely full or the first jug itself is empty.
12 Input: x = 2, y = 6, z = 4Output: True
12 Input: x = 2, y = 6, z = 5Output: False
leetcode Max Sum of Rectangle No Larger Than K
Given a non-empty 2D matrix matrix and an integer k, find the max sum of a rectangle in the matrix such that its sum is no larger than k.
12345 Given matrix = [[1, 0, 1],[0, -2, 3]]k = 2
The answer is
2. Because the sum of rectangle
[[0, 1], [-2, 3]]is 2 and 2 is the max number no larger than k (k = 2).
- The rectangle inside the matrix must have an area > 0.
- What if the number of rows is much larger than the number of columns?
leetcode Count Numbers with Unique Digits
Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10n.
Given n = 2, return 91. (The answer should be the total numbers in the range of 0 ≤ x < 100, excluding
leetcode Design Twitter
Design a simplified version of Twitter where users can post tweets, follow/unfollow another user and is able to see the 10 most recent tweets in the user’s news feed. Your design should support the following methods:
- postTweet(userId, tweetId): Compose a new tweet.
- getNewsFeed(userId): Retrieve the 10 most recent tweet ids in the user’s news feed. Each item in the news feed must be posted by users who the user followed or by the user herself. Tweets must be ordered from most recent to least recent.
- follow(followerId, followeeId): Follower follows a followee.
- unfollow(followerId, followeeId): Follower unfollows a followee.
123456789101112131415161718192021222324 Twitter twitter = new Twitter();// User 1 posts a new tweet (id = 5).twitter.postTweet(1, 5);// User 1's news feed should return a list with 1 tweet id -> .twitter.getNewsFeed(1);// User 1 follows user 2.twitter.follow(1, 2);// User 2 posts a new tweet (id = 6).twitter.postTweet(2, 6);// User 1's news feed should return a list with 2 tweet ids -> [6, 5].// Tweet id 6 should precede tweet id 5 because it is posted after tweet id 5.twitter.getNewsFeed(1);// User 1 unfollows user 2.twitter.unfollow(1, 2);// User 1's news feed should return a list with 1 tweet id -> ,// since user 1 is no longer following user 2.twitter.getNewsFeed(1);