IC 150 — Complete Interview Prep

We have two special characters: Given a binary array bits that ends with 0, return true if the last character must be a one-bit character.

The array-form of an integer num is an array representing its digits in left to right order.

Given an array nums of n integers and an integer k, determine whether there exist two adjacent subarrays of length k such that both subarrays are strictly increasing.

There is a circle of red and blue tiles.

Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <= k.

You are given a binary string s and an integer k.

An ant is on a boundary.

You are given a 2D integer array ranges and two integers left and right.

You are given an integer array nums of length n.

Given two strings s and t, return true if they are equal when both are typed into empty text editors.

You are given a string s.

A file system keeps a log each time some user performs a change folder operation.

Given a string s, find the first non-repeating character in it and return its index.

The school cafeteria offers circular and square sandwiches at lunch break, referred to by numbers 0 and 1 respectively.

There are n people in a line queuing to buy tickets, where the 0th person is at the front of the line and the (n - 1)th person is at the back of the line.

You are given an integer array prices where prices[i] is the price of the ith item in a shop.

The next greater element of some element x in an array is the first greater element that is to the right of x in the same array.

Given an array of n integers nums, a 132 pattern is a subsequence of three integers nums[i], nums[j] and nums[k] such that i < j < k and nums[i] < nums[k] < nums[j].

You are given a 0-indexed integer array nums.

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

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

You are given an array apple of size n and an array capacity of size m.

You are given a 0-indexed array nums of size n consisting of non-negative integers.

Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), ..., (an, bn) such that the sum of min(ai, bi) for all i is maximized.

You have a bomb to defuse, and your time is running out!

The k-beauty of an integer num is defined as the number of substrings of num when it is read as a string that meet the following conditions: Given integers num and k, return the...

You are given an array nums of n integers and two integers k and x.

Given an array of integers nums, calculate the pivot index of this array.

There is a biker going on a road trip.

Given a 0-indexed integer array nums, find the leftmost middleIndex (i.e., the smallest amongst all the possible ones).

Given a string s of lower and upper case English letters.

Given a valid parentheses string s, return the nesting depth of s.

You are given a string s consisting only of uppercase English letters.

In the world of Dota2, there are two parties: the Radiant and the Dire.

There are n friends that are playing a game.

You are given a 0-indexed integer array nums and an integer k.

You are given an array heights of n integers representing the number of bricks in n consecutive towers.

You are given a 0-indexed array maxHeights of n integers.

There are n cars at given miles away from the starting mile 0, traveling to reach the mile target.

Given an array of integers nums and an integer limit, return the size of the longest non-empty subarray such that the absolute difference between any two elements of this subarray...

Given a circular integer array nums of length n, return the maximum possible sum of a non-empty subarray of nums.

You are given an 0-indexed integer array prices where prices[i] denotes the number of coins needed to purchase the (i + 1)th fruit.

Determine whether a singly-linked list loops back on itself instead of ending in null.

Splice two sorted singly-linked lists together into a single sorted list.

Find the value stored in the middle node of a singly-linked list in a single pass.

You have n coins and you want to build a staircase with these coins.

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums.

Given an array arr of integers, check if there exist two indices i and j such that :

You are given an m x n matrix grid consisting of positive integers.

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

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

Assume you are an awesome parent and want to give your children some cookies.

You are given an integer array prices representing the prices of various chocolates in a store.

You have a long flowerbed in which some of the plots are planted, and some are not.

You are given a 0-indexed string array words.

Write a function to find the longest common prefix string amongst an array of strings.

You are given a 0-indexed integer array nums.

Return every root-to-leaf path in a binary tree as a list of node values, instead of an arrow-joined string.

Return every root-to-leaf path in a binary tree as an arrow-joined string.

A binary watch has 4 LEDs on the top to represent the hours (0-11), and 6 LEDs on the bottom to represent the minutes (0-59).

Given an array nums, you can perform the following operation any number of times: Return the minimum number of operations needed to make the array non-decreasing.

Check whether the values in a singly-linked list read the same forwards and backwards.

Collapse consecutive duplicate values in a sorted singly-linked list so each value appears once.

Given a m x n matrix grid which is sorted in non-increasing order both row-wise and column-wise, return the number of negative numbers in grid.

You are given a 0-indexed array of positive integers nums.

Alice and Bob have a different total number of candies.

You are given a positive integer num.

You are given an array of integers stones where stones[i] is the weight of the ith stone.

You are given a non-negative integer array nums.

A permutation perm of n + 1 integers of all the integers in the range [0, n] can be represented as a string s of length n where: Given a string s, reconstruct the permutation perm...

You are given an integer money denoting the amount of money (in dollars) that you have and another integer children denoting the number of children that you must distribute the...

There is a bag that consists of items, each item has a number 1, 0, or -1 written on it.

Given an array of strings queries and a string pattern, return a boolean array answer where answer[i] is true if queries[i] matches pattern, and false otherwise.

You are given a 0-indexed string s and a dictionary of words dictionary.

You are given two arrays with positive integers arr1 and arr2.

The XOR total of an array is defined as the bitwise XOR of all its elements, or 0 if the array is empty.

An additive number is a string whose digits can form an additive sequence.

Given a directed acyclic graph (DAG) of n nodes labeled from 0 to n - 1, find all possible paths from node 0 to node n - 1 and return them in any order.

An introduction to the Node and BinTree building blocks used throughout the Binary Trees series, plus a sample tree these exercises build on.

Add preorder, inorder, and postorder traversal methods to BinTree and see how each visits the same sample tree in a different order.

Build a height-balanced binary search tree from an array sorted in ascending order.

There is a bi-directional graph with n vertices, where each vertex is labeled from 0 to n - 1 (inclusive).

You are given an image represented by an m x n grid of integers image, where image[i][j] represents the pixel value of the image.

You are given row x col grid representing a map where grid[i][j] = 1 represents land and grid[i][j] = 0 represents water.

Given an m x n binary matrix mat, return the distance of the nearest 0 for each cell.

Given a list of accounts where each element accounts[i] is a list of strings, where the first element accounts[i][0] is a name, and the rest of the elements are emails...

Given an n x n grid containing only values 0 and 1, where 0 represents water and 1 represents land, find a water cell such that its distance to the nearest land cell is maximized,...

There is an undirected star graph consisting of n nodes labeled from 1 to n.

In a town, there are n people labeled from 1 to n.

There are n cities connected by some number of flights.

There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1.

There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1.

There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1.

You are given an m x n grid.

You are given an m x n matrix grid and a positive integer k.

You are given a map of a server center, represented as a m * n integer matrix grid, where 1 means that on that cell there is a server and 0 means that it is no server.

Flip a binary tree into its mirror image by swapping every node's left and right children.

Find the smallest absolute difference between the values of any two distinct nodes in a binary search tree.

Sum every node value in a binary search tree that falls within a given inclusive range.

You are given an integer array nums of length n where nums is a permutation of the numbers in the range [0, n - 1].

Given an m x n matrix board where each cell is a battleship 'X' or empty '.', return the number of the battleships on board.

There is a room with n bulbs labeled from 1 to n that all are turned on initially, and four buttons on the wall.

There is a knight on an n x n chessboard.

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money.

You are given an m x n integer matrix grid, and three integers row, col, and color.

You are given an integer n.

You are given three positive integers n, x, and y.

You are given an integer n.

You have information about n different recipes.

There is a directed graph of n nodes with each node labeled from 0 to n - 1.

There is a group of n people labeled from 0 to n - 1 where each person has a different amount of money and a different level of quietness.

You are given two m x n binary matrices grid1 and grid2 containing only 0's (representing water) and 1's (representing land).

Given a 2D array of characters grid of size m x n, you need to find if there exists any cycle consisting of the same value in grid.

You are given an array of variable pairs equations and an array of real numbers values, where equations[i] = [Ai, Bi] and values[i] represent the equation Ai / Bi = values[i].

You are given two integers n and m that consist of the same number of digits.

You are given an m x n binary matrix grid and an integer health.

There is a dungeon with n x m rooms arranged as a grid.

You are given an array points representing integer coordinates of some points on a 2D-plane, where points[i] = [xi, yi].

Given a weighted undirected connected graph with n vertices numbered from 0 to n - 1, and an array edges where edges[i] = [ai, bi, weighti] represents a bidirectional and weighted...

You are given an integer n, representing n nodes numbered from 0 to n - 1 and a list of edges, where edges[i] = [ui, vi, si, musti]: You are also given an integer k, the maximum...

There is a safe protected by a password.

There are n servers numbered from 0 to n - 1 connected by undirected server-to-server connections forming a network where connections[i] = [ai, bi] represents a connection between...

There is an undirected tree with n nodes labeled from 0 to n - 1.

You are given an array prices where prices[i] is the price of a given stock on the ith day.

You are climbing a staircase.

Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1's in the binary representation of i.

You are given two arrays of integers, fruits and baskets, each of length n, where fruits[i] represents the quantity of the ith type of fruit, and baskets[j] represents the...

There are n soldiers standing in a line.

You are given two arrays of integers, fruits and baskets, each of length n, where fruits[i] represents the quantity of the ith type of fruit, and baskets[j] represents the...

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.

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

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

There is a dungeon with n x m rooms arranged as a grid.

There are n cities numbered from 0 to n-1.

You are given two integers, n and threshold, as well as a directed weighted graph of n nodes numbered from 0 to n - 1.

You are given an m x n binary grid grid where 1 represents land and 0 represents water.

You are given a list of airline tickets where tickets[i] = [fromi, toi] represent the departure and the arrival airports of one flight.

You are given a 0-indexed 2D integer array pairs where pairs[i] = [starti, endi].

Alice and Bob take turns playing a game, with Alice starting first.

The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1.

Given two strings s and t, return true if s is a subsequence of t, or false otherwise.

You are given an array of strings words and a string target.

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

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

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...

There are some red and blue tiles arranged circularly.

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