Community Profile

photo

David Arnold


61 total contributions since 2018

David Arnold's Badges

  • Solver

View details...

Contributions in
View by

Solved


Elapsed Time
Given two date strings d1 and d2 of the form yyyy/mm/dd HH:MM:SS (assume hours HH is in 24 hour mode), determine how much time, ...

1년 이상 ago

Solved


Find state names that end with the letter A
Given a list of US states, remove all the states that end with the letter A. Example: Input s1 = 'Alabama Montana Nebras...

1년 이상 ago

Solved


The Goldbach Conjecture, Part 2
The <http://en.wikipedia.org/wiki/Goldbach's_conjecture Goldbach conjecture> asserts that every even integer greater than 2 can ...

1년 이상 ago

Solved


The Goldbach Conjecture
The <http://en.wikipedia.org/wiki/Goldbach's_conjecture Goldbach conjecture> asserts that every even integer greater than 2 can ...

1년 이상 ago

Solved


Pattern matching
Given a matrix, m-by-n, find all the rows that have the same "increase, decrease, or stay same" pattern going across the columns...

1년 이상 ago

Solved


Tic Tac Toe FTW
Given a tic tac toe board: * 1 represents X * 0 represents empty. * -1 represents O It is X's move. If there is an imme...

1년 이상 ago

Solved


Summing Digits within Text
Given a string with text and digits, add all the numbers together. Examples: Input str = '4 and 20 blackbirds baked in a...

1년 이상 ago

Solved


Scrabble Scores
Given a word, determine its score in <http://en.wikipedia.org/wiki/Scrabble Scrabble>. The input string will always be provi...

1년 이상 ago

Solved


Counting Sequence
Given a vector x, find the "counting sequence" y. A counting sequence is formed by "counting" the entries in a given sequence...

1년 이상 ago

Solved


Maximum running product for a string of numbers
Given a string s representing a list of numbers, find the five consecutive numbers that multiply to form the largest number. Spe...

1년 이상 ago

Solved


Duplicates
Write a function that accepts a cell array of strings and returns another cell array of strings *with only the duplicates* retai...

1년 이상 ago

Solved


What is the next step in Conway's Life?
Given a matrix A that represents the state of <http://en.wikipedia.org/wiki/Conway's_Game_of_Life Conway's game of Life> at one ...

1년 이상 ago

Solved


Find the two most distant points
Given a collection of points, return the indices of the rows that contain the two points most distant from one another. The inpu...

1년 이상 ago

Solved


Sums with Excluded Digits
Add all the integers from 1 to n in which the digit m does not appear. m will always be a single digit integer from 0 to 9. no...

1년 이상 ago

Solved


Making change
Given an amount of currency, return a vector of this form: [100 50 20 10 5 2 1 0.5 0.25 0.1 0.05 0.01] Example: Input a = ...

1년 이상 ago

Solved


Extract leading non-zero digit
<http://en.wikipedia.org/wiki/Benford%27s_law Benford's Law> states that the distribution of leading digits is not random. This...

1년 이상 ago

Solved


Which doors are open?
There are n doors in an alley. Initially they are all shut. You have been tasked to go down the alley n times, and open/shut the...

1년 이상 ago

Solved


Make a Palindrome Number
Some numbers like 323 are palindromes. Other numbers like 124 are not. But look what happens when we add that number to a revers...

1년 이상 ago

Solved


Subset Sum
Given a vector v of integers and an integer n, return the the indices of v (as a row vector in ascending order) that sum to n. I...

1년 이상 ago

Solved


Trimming Spaces
Given a string, remove all leading and trailing spaces (where space is defined as ASCII 32). Input a = ' singular value deco...

1년 이상 ago

Solved


Find the alphabetic word product
If the input string s is a word like 'hello', then the output word product p is a number based on the correspondence a=1, b=2, ....

1년 이상 ago

Solved


Cell joiner
You are given a cell array of strings and a string delimiter. You need to produce one string which is composed of each string fr...

1년 이상 ago

Solved


Reverse Run-Length Encoder
Given a "counting sequence" vector x, construct the original sequence y. A counting sequence is formed by "counting" the entrie...

1년 이상 ago

Solved


Which values occur exactly three times?
Return a list of all values (sorted smallest to largest) that appear exactly three times in the input vector x. So if x = [1 2...

1년 이상 ago

Solved


Return a list sorted by number of occurrences
Given a vector x, return a vector y of the unique values in x sorted by the number of occurrences in x. Ties are resolved by a ...

1년 이상 ago

Solved


Pascal's Triangle
Given an integer n >= 0, generate the length n+1 row vector representing the n-th row of <http://en.wikipedia.org/wiki/Pascals_t...

1년 이상 ago

Solved


Find relatively common elements in matrix rows
You want to find all elements that exist in greater than 50% of the rows in the matrix. For example, given A = 1 2 3 5 ...

1년 이상 ago

Solved


Binary numbers
Given a positive, scalar integer n, create a (2^n)-by-n double-precision matrix containing the binary numbers from 0 through 2^n...

1년 이상 ago

Solved


Quote Doubler
Given a string s1, find all occurrences of the single quote character and replace them with two occurrences of the single quote ...

1년 이상 ago

Solved


Create times-tables
At one time or another, we all had to memorize boring times tables. 5 times 5 is 25. 5 times 6 is 30. 12 times 12 is way more th...

1년 이상 ago

Load more