InterviewCoding

Fenwick Tree

Twenty questions on Fenwick trees (binary indexed trees), a compact alternative to segment trees for prefix-sum queries.

Count Number of Rectangles Containing Each Point

You are given a 2D integer array rectangles where rectangles[i] = [li, hi] indicates that ith rectangle has a length of li and a height of hi.

Count Number of Teams

There are n soldiers standing in a line.

Maximum Area Rectangle With Point Constraints I

You are given an array points where points[i] = [xi, yi] represents the coordinates of a point on an infinite plane.

Number of Longest Increasing Subsequence

Given an integer array nums, return the number of longest increasing subsequences.

Queries on a Permutation With Key

Given the array queries of positive integers between 1 and m, you have to process all queries[i] (from i=0 to i=queries.length-1) according to the following rules: Return an array...

Queue Reconstruction by Height

You are given an array of people, people, which are the attributes of some people in a queue (not necessarily in order).

Alternating Groups III

There are some red and blue tiles arranged circularly.

Block Placement Queries

There exists an infinite number line, with its origin at 0 and extending towards the positive x-axis.

Count Good Triplets in an Array

You are given two 0-indexed arrays nums1 and nums2 of length n, both of which are permutations of [0, 1, ..., n - 1].

Count Increasing Quadruplets

Given a 0-indexed integer array nums of size n containing all numbers from 1 to n, return the number of increasing quadruplets.

Count of Range Sum

Given an integer array nums and two integers lower and upper, return the number of range sums that lie in [lower, upper] inclusive.

Count of Smaller Numbers After Self

Given an integer array nums, return an integer array counts where counts[i] is the number of smaller elements to the right of nums[i].

Create Sorted Array through Instructions

Given an integer array instructions, you are asked to create a sorted array from the elements in instructions.

Distribute Elements Into Two Arrays II

You are given a 1-indexed array of integers nums of length n.

Find Building Where Alice and Bob Can Meet

You are given a 0-indexed array heights of positive integers, where heights[i] represents the height of the ith building.

Find the Longest Valid Obstacle Course at Each Position

You want to build some obstacle courses.

Longest Increasing Subsequence II

You are given an integer array nums and an integer k.

Make Array Empty

You are given an integer array nums containing distinct numbers, and you can perform the following operations until the array is empty: Return an integer denoting the number of...

Maximum Area Rectangle With Point Constraints II

There are n points on an infinite plane.

Maximum Balanced Subsequence Sum

You are given a 0-indexed integer array nums.