Description: Write a function that, given a string of text (possibly with punctuation and line-breaks), returns an array of the top-3 most occurring words, in descending order of the number of occurrences.
Assumptions:
- A word is a string of letters (A to Z) optionally containing one or more apostrophes (') in ASCII. (No need to handle fancy punctuation.)
- Matches should be case-insensitive, and the words in the result should be lowercased.
- Ties may be broken arbitrarily.
- If a text contains fewer than three unique words, then either the top-2 or top-1 words should be returned, or an empty array if a text contains no words.
top_3_words("In a village of La Mancha, the name of which I have no desire to call to
mind, there lived not long since one of those gentlemen that keep a lance
in the lance-rack, an old buckler, a lean hack, and a greyhound for
coursing. An olla of rather more beef than mutton, a salad on most
nights, scraps on Saturdays, lentils on Fridays, and a pigeon or so extra
on Sundays, made away with three-quarters of his income.")
# => ["a", "of", "on"]
top_3_words("e e e e DDD ddd DdD: ddd ddd aa aA Aa, bb cc cC e e e")
# => ["e", "ddd", "aa"]
top_3_words(" //wont won't won't")
# => ["won't", "wont"]'''
You have a list of integers, and for each index you want to find the product of every integer except the integer at that index. Write a function get_products_of_all_ints_except_at_index() that takes a list of integers and returns a list of the products.
For example, given:
[1, 7, 3, 4]
your function would return:
[84, 12, 28, 21]
by calculating:
[7*3*4, 1*3*4, 1*7*4, 1*7*3]
Do not use division in your solution.
Your company built an in-house calendar tool called HiCal. You want to add a feature to see the times in a day when everyone is available.To do this, you’ll need to know when any team is having a meeting. In HiCal, a meeting is stored as arrays of integers [start_time, end_time]. These integers represent the number of 30-minute blocks past 9:00am.
For example:
[2, 3] # meeting from 10:00 – 10:30 am
[6, 9] # meeting from 12:00 – 1:30 pm
Write a function condense_meeting_times() that takes an array of meeting time ranges and returns an array of condensed ranges.
For example, given:
[ [0, 1], [3, 5], [4, 8], [10, 12], [9, 10] ]
your function would return:
[ [0, 1], [3, 8], [9, 12] ]
Do not assume the meetings are in order. The meeting times are coming from multiple teams.
Write a solution that's efficient even when we can't put a nice upper bound on the numbers representing our time ranges. Here we've simplified our times down to the number of 30-minute slots past 9:00 am. But we want the function to work even for very large numbers, like Unix timestamps. In any case, the spirit of the challenge is to merge meetings where start_time and end_time don't have an upper bound.
Suppose we could access yesterday's stock prices as a list, where:
The indices are the time in minutes past trade opening time, which was 9:30am local time. The values are the price in dollars of Apple stock at that time. So if the stock cost $500 at 10:30am, stock_prices_yesterday[60] = 500.
Write an efficient function that takes stock_prices_yesterday and returns the best profit I could have made from 1 purchase and 1 sale of 1 Apple stock yesterday.
For example:
stock_prices_yesterday = [10, 7, 5, 8, 11, 9]
get_max_profit(stock_prices_yesterday)
returns 6 (buying for $5 and selling for $11)
No "shorting"—you must buy before you sell. You may not buy and sell in the same time step (at least 1 minute must pass).
A Hamming number is a positive integer of the form 2i3j5k, for some non-negative integers i, j, and k.
Write a function that computes the nth smallest Hamming number.
Specifically:
The first smallest Hamming number is 1 = 203050 The second smallest Hamming number is 2 = 213050 The third smallest Hamming number is 3 = 203150 The fourth smallest Hamming number is 4 = 223050 The fifth smallest Hamming number is 5 = 203051 The 20 smallest Hamming numbers are given in example test fixture.
Your code should be able to compute all of the smallest 5,000 Hamming numbers without timing out.
In this kata you will have to calculate fib(n) where:
fib(0) = 0
fib(1) = 1
fin(n + 2) = fib(n + 1) + fib(n)
Write an algorithm that can handle n where 1000000 ≤ n ≤ 1500000.
Your algorithm must output the exact integer answer, to full precision. Also, it must correctly handle negative numbers as input.
HINT I: Can you rearrange the equation fib(n + 2) = fib(n + 1) + fib(n) to find fib(n) if you already know fin(n + 1) and fib(n + 2)? Use this to reason what value fib has to have for negative values.
HINT II: See http://mitpress.mit.edu/sicp/chapter1/node15.html
Write a function to find the 2nd largest element in a binary search tree ↴ . Here's a sample binary tree node class:
class BinaryTreeNode
attr_accessor :value
attr_reader :left, :right
def initialize(value)
@value = value
@left = nil
@right = nil
end
def insert_left(value)
@left = BinaryTreeNode.new(value)
return @left
end
def insert_right(value)
@right = BinaryTreeNode.new(value)
return @right
end
end
Consider a "word" as any sequence of capital letters A-Z (not limited to just "dictionary words"). For any word with at least two different letters, there are other words composed of the same letters but in a different order (for instance, STATIONARILY/ANTIROYALIST, which happen to both be dictionary words; for our purposes "AAIILNORSTTY" is also a "word" composed of the same letters as these two).
We can then assign a number to every word, based on where it falls in an alphabetically sorted list of all words made up of the same group of letters. One way to do this would be to generate the entire list of words and find the desired one, but this would be slow if the word is long.
Given a word, return its number. Your function should be able to accept any word 25 letters or less in length (possibly with some letters repeated), and take no more than 500 milliseconds to run. To compare, when the solution code runs the 27 test cases in JS, it takes 101ms.
Sample words, with their rank: ABAB = 2 AAAB = 1 BAAA = 4 QUESTION = 24572 BOOKKEEPER = 10743
Given two valid dictionary words of same length, write a function which returns the minimum number of steps to go from the first to the second word. You can change only one character at a time. Also, the word formed at every step should be a valid dictionary word.
Eg: Provide minimum steps to go from 'cat' to 'dog'
cat -> bat -> bet -> bot -> bog -> dog (Ans: 5)