This problem was asked by Quora. Given an absolute pathname that may have . or .. as part of it, return the shortest standardized path. For example, given /usr/bin/../bin/./scripts/../, return /usr/bin/.
Difficulty: Medium
This problem was asked by Amazon. Run-length encoding is a fast and simple method of encoding strings. The basic idea is to represent repeated successive characters as a single count and character. For example, the string AAAABBBCCDAA would be encoded as 4A3B2C1D2A.
Implement run-length encoding and decoding. You can assume the string to be encoded have no digits and consists solely of alphabetic characters. You can assume the string to be decoded is valid.
Difficulty: Easy
This problem was asked by Microsoft. Compute the running median of a sequence of numbers. That is, given a stream of numbers, print out the median of the list. Recall that the median of an even-numbered list is the average of the two middle numbers.
Difficulty: Easy
This problem was asked by Microsoft. Given a string of numbers, return all possible permutations.
Difficulty: Easy
This problem was asked by Google. Given a string of words delimited by spaces, reverse the words in string. For example, given "hello world here", return "here world hello"
Difficulty: Medium
This problem was asked by Google. Given a sorted list of integers, square the elements and give the output in sorted order. For example, given [-9, -2, 0, 2, 3], return [0, 4, 4, 9, 81].
Difficulty: Easy
Given a real number "n", find the square root of "n". For example, given n=9, return 3.
Difficulty: Medium
This problem was asked by Google. Given the head of a singly linked list, swap every two nodes and return its head. For example, given 1 -> 2 -> 3 -> 4, return 2 -> 1 -> 4 -> 3.
Difficulty: Easy
This problem was asked by Google. Given a string, return the first recurring character in it, or null if there is no recurring character. For example, given the string acbbac, return b. Given the string abcdef, return null.
Difficulty: Easy
Write a function to get the last element of an array. Passing a parameter 'n' will return the last 'n' elements of the array.
Difficulty: Easy
Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order.
Difficulty: Easy
This problem was asked by Google. Given an array of elements, return the length of the longest subarray where all its elements are distinct. For example, given the array [5, 1, 3, 5, 2, 3, 4, 1], return 5 as the longest subarray of distinct elements is [5, 2, 3, 4, 1].
Difficulty: Easy
This problem was asked by Microsoft. Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example, given [100, 4, 200, 1, 3, 2], the longest consecutive element sequence is [1, 2, 3, 4]. Return its length: 4. Your algorithm should run in O(n) complexity.
Difficulty: Medium
This problem was asked by Google. Given a string, split it into as few strings as possible such that each string is a palindrome. For example, given the input string racecarannakayak, return ["racecar", "anna", "kayak"]. Given the input string abc, return ["a", "b", "c"].
Difficulty: Medium
This problem was asked by Palantir. Write a program that checks whether an integer is a palindrome. For example, 121 is a palindrome, as well as 888. 678 is not a palindrome. Do not convert the integer into a string.
This problem was asked by Google. The power set of a set is the set of all its subsets. Write a function that, given a set, generates its power set. For example, given the set {1, 2, 3}, it should return {{}, {1}, {2}, {3}, {1, 2}, {1, 3}, {2, 3}, {1, 2, 3}}. You may also use a list or array to represent a set.
Difficulty: Easy
This problem was asked by Amazon. Given a N by M matrix of numbers, print out the matrix in a clockwise spiral. For example, given the following matrix:
[ [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20] ] You should print out the following:
1, 2, 34 ,5 ,10 ,15 ,20 ,19 ,18 ,17 ,16 ,11 ,6 ,7 ,8 ,9 ,14 ,13 ,12
Difficulty: Easy
Given an integer array, output all distinct pairs that sum up to a specific value k. Consider the fact that the same number can add up to k with its duplicates in the array.
For example the array is [1, 1, 2, 3, 4] and the desired sum is 4. Should we output the pair (1, 3) twice or just once? Also do we output the reverse of a pair, meaning both (3, 1) and (1, 3)? Let’s keep the output as short as possible and print each pair only once. So, we will output only one copy of (1, 3). Also note that we shouldn’t output (2, 2) because it’s not a pair of two distinct elements.
arrayPairSum([3, 4, 5, 6, 7], 10) // [ [4, 6], [3, 7] ] arrayPairSum([3, 4, 5, 4, 4], 8) // [ [3, 5], [4, 4], [4, 4], [4, 4] ] arrayPairSum([3, 5, 6, 8], 10) // []
Difficulty: Medium
There is an array of non-negative integers. A second array is formed by shuffling the elements of the first array and deleting a random element. Given these two arrays, find which element is missing in the second array.
Difficulty: Easy
By definition, the first two numbers in the Fibonacci sequence are 0 and 1, and each subsequent number is the sum of the previous two.
For example, the first ten Fibonacci numbers are: "0, 1, 1, 2, 3, 5, 8, 13, 21, 34" Write a function that accepts a number and returns the number at that position in the fibonnaci sequence.
Difficulty: Medium
Write a function that accepts an array of random integers and an integer n. Determine the number of times where two integers in the array have the difference of n. console.log(integerDifference([1, 1, 5, 6, 9, 16, 27], 4)); //8 console.log(integerDifference([1, 1, 3, 3], 2)); //6
Difficutlry: Easy
Write a function that accepts a multi dimensional array and returns a flattened version. flattenedArray([1, 2, [3, [4], 5, 6], 7]); //[1, 2, 3, 4, 5, 6, 7] flattenedArray([1, [3, [4, [9, [0]]]], 7]); //[1, 3, 4, 9, 0, 7]
Difficulty: Easy
Given an imaginary chess board of size m x n including only the Queen and the King write a function that takes the positions (coordinates) of both the Queen and the King as parameters and returns a boolean telling whether or not the King is threatened by the Queen.
Difficulty: Medium
Write a function that takes two inputs "n" and "m" and outputs the number of the unique paths from the top left cotner to the bottom right corner of a "n"x"m" grid. Constraints: you can only move down or right 1 unit at a time.
Difficulty: Hard
Write a function that takes input "n" and outputs the factorial of the given number. (A factorial is a function that multiplies a number by every number below it. For example 5!= 54321=120.)
Difficulty: Easy
This problem was asked by Stripe. Given an array of integers, find the first missing positive integer in linear time and constant space. In other words, find the lowest positive integer that does not exist in the array. The array can contain duplicates and negative numbers as well.
For example, the input [3, 4, -1, 1] should give 2. The input [1, 2, 0]should give 3. You can modify the input array in-place.
Difficulty: Easy
Writa a roman numeral converter function.
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Six special instances:
- I can be placed before V (5) and X (10) to make 4 and 9.
- X can be placed before L (50) and C (100) to make 40 and 90.
- C can be placed before D (500) and M (1000) to make 400 and 900.
Difficulty: Medium
Given a string s consisting of words and spaces, return the length of the last word in the string.
A word is a maximal substring consisting of non-space characters only.
Difficulty: Easy
You are given a large integer represented as an integer array digits, where each digits[i] is the ith digit of the integer. The digits are ordered from most significant to least significant in left-to-right order. The large integer does not contain any leading 0's.
Increment the large integer by one and return the resulting array of digits. Ex.: [9,9] -> [1,0,0]; [3,5,9] -> [3,6,0]
Difficulty: Easy
You are climbing a staircase. It takes n steps to reach the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Constraints: 1 <= n <= 45
Difficulty: Easy
Given an integer x, return x with its digits reversed. EX.: x=123 -> 321; x=-123 -> -321; x=120 -> 21
Difficulty: Easy
Given the array nums consisting of 2n elements in the form [x1,x2,...,xn,y1,y2,...,yn].
Return the array in the form [x1,y1,x2,y2,...,xn,yn].
Ex.: nums = [2,5,1,3,4,7], n = 3 => [2,3,5,4,1,7]
Difficulty: Easy
You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).
Find two lines that together with the x-axis form a rectangle. Return the biggest area of a possible rectangle.
Ex.: maxArea(height = [1,8,6,2,5,4,8,3,7]) //49
-> 8 & 7 -> one side is 7 and the other one is 7 => 49
Difficulty: Medium
You are given an array of strings ideas that represents a list of names to be used in the process of naming a company. The process of naming a company is as follows:
Choose 2 distinct names from ideas, call them ideaA and ideaB. Swap the first letters of ideaA and ideaB with each other. If both of the new names are not found in the original ideas, then the name ideaA ideaB (the concatenation of ideaA and ideaB, separated by a space) is a valid company name.
Otherwise, it is not a valid name. Return the number of distinct valid names for the company.
Ex:. findName(["coffee","donuts","toffee"]) //4
"cime doffee", "doffee cime", ...
findName(["lack","back"])) //0
Difficulty: Medium
Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays. Ex.: console.log(Median([1,3,4], [2])) //2.5
Difficulty: Medium
Given two non-negative integers low and high. Return the count of odd numbers between low and high (inclusive).
Difficulty: Easy
Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator.
The integer division should truncate toward zero, which means losing its fractional part. For example, 8.345 would be truncated to 8, and -2.7335 would be truncated to -2.
Return the quotient after dividing dividend by divisor.
Difficulty: Medium
Given an integer numRows, return the first numRows of Pascal's triangle.
In Pascal's triangle, each number is the sum of the two numbers directly above it as shown:
Ex.: numRows(5) => [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]
Difficulty: Medium
Given an integer numRows, return the last numRow of Pascal's triangle.
In Pascal's triangle, each number is the sum of the two numbers directly above it as shown:
Ex.: numRows(5) => [1,4,6,4,1]
Difficulty: Medium
There are n children standing in a line. Each child is assigned a rating value given in the integer array ratings.
You are giving candies to these children subjected to the following requirements:
- Each child must have at least one candy.
- Children with a higher rating get more candies than their neighbors.
Return the minimum number of candies you need to have to distribute the candies to the children.
Koko loves to eat bananas. There are n piles of bananas, the ith pile has piles[i] bananas. The guards have gone and will come back in h hours.
Koko can decide her bananas-per-hour eating speed of k. Each hour, she chooses some pile of bananas and eats k bananas from that pile. If the pile has less than k bananas, she eats all of them instead and will not eat any more bananas during this hour.
Koko likes to eat slowly but still wants to finish eating all the bananas before the guards return.
Return the minimum integer k such that she can eat all the bananas within h hours.
Ex.: piles: [3,6,7,11], h: 8 => return 4
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