819. Most Common Word

Description

Given a string paragraph and a string array of the banned words banned, return the most frequent word that is not banned. It is guaranteed there is at least one word that is not banned, and that the answer is unique .

1232. Check If It Is a Straight Line

Description

You are given an arraycoordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these pointsmake a straight line in the XY plane.

559. Maximum Depth of N-ary Tree

Description

Given a n-ary tree, find its maximum depth.

489. Robot Room Cleaner

Description

You are controlling a robot that is located somewhere in a room. The room is modeled as an m x n binary grid where 0 represents a wall and 1 represents an empty slot.

359. Logger Rate Limiter

Description

Design a logger system that receives a stream of messages along with their timestamps. Each unique message should only be printed at most every 10 seconds (i.e. a message printed at timestamp t will prevent other identical messages from being printed until timestamp t + 10).

480. Sliding Window Median

Description

The median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle values.

245. Shortest Word Distance III

Description

Given an array of strings wordsDict and two strings that already exist in the array word1 and word2, return the shortest distance between the occurrence of these two words in the list.

1028. Recover a Tree From Preorder Traversal

Description

We run a preorder depth-first search (DFS) on the root of a binary tree.

311. Sparse Matrix Multiplication

Description

Given two sparse matrices mat1 of size m x k and mat2 of size k x n, return the result of mat1 x mat2. You may assume that multiplication is always possible.

1443. Minimum Time to Collect All Apples in a Tree

Description

Given an undirected tree consisting of n vertices numbered from 0 to n-1, which has some apples in their vertices. You spend 1 second to walk over one edge of the tree. Return the minimum time in seconds you have to spend to collect all apples in the tree, starting at vertex 0 and coming back to this vertex.