Problem

Matrix indexing with two vectors of indices (★★)
(copy of Prob 589) Given a matrix M and two index vectors a and b, return a row vector x where x(i) = M(a(i),b(i)). Thus, if...

6 years ago | 0 | 46 solvers

Problem

Reindex a vector (★★)
(copy of Prob. 676) You are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX h...

6 years ago | 0 | 59 solvers

Problem

Get the elements of diagonal and antidiagonal for any m-by-n matrix (★★★★)
(copy of prob. 859) In this problem you must submit a solution which returns the diagonal and anti-diagonal elements without ...

6 years ago | 0 | 33 solvers

Problem

Replicate elements in vectors (★★★)
(copy of Prob 867) Replicate each element of a row vector (with NaN) a constant number of times. Examples n=2, A=[1 2...

6 years ago | 0 | 63 solvers

Problem

Remove the row average (★★★)
(copy of Prob. 963) Given a 2-d matrix, remove the row average from each row. Your solution MUST be vectorized. The solut...

6 years ago | 2 | 46 solvers

Problem

Average of corner elements of a matrix (★★)
(copy of prob 2235) Calculate the average of corner elements of a matrix. e.g. x=[1 2 3; 4 5 6; 7 8 9;] avg = (1+3+7+9)...

6 years ago | 0 | 87 solvers

Problem

Generate a vector which contains a pyramid pattern (★★★★)
Generate a vector that contains terms that follows a pyramid pattern up to the nth row: 1 2 2 3 3 3 4 4 4 4 ...

6 years ago | 1 | 67 solvers

Problem

Doubling elements in a vector (★★)
(copy of prob. 1024) Given the vector A, return B in which all numbers in A are doubling. So for: A = [ 1 5 8 ] t...

6 years ago | 0 | 99 solvers

Problem

Create times-tables (★★★)
(copy of prob 33) At one time or another, we all had to memorize boring times tables. 5 times 5 is 25. 5 times 6 is 30. 12 ti...

6 years ago | 0 | 86 solvers

Problem

Swap the first and last columns (★★)
(copy of Prob 19) Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becom...

6 years ago | 0 | 120 solvers

Problem

Column Removal (★★★)
(copy of prob 7) Remove the nth column from input matrix A and return the resulting matrix in output B. So if A = [1 2...

6 years ago | 1 | 384 solvers

Problem

Select every other element of a vector (★★)
(copy of prob 6) Write a function which returns every other element of the vector passed in. That is, it returns the all odd-...

6 years ago | 2 | 112 solvers

Problem

Triangle Numbers (★★)
(copy of problem 5) Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3...

6 years ago | 0 | 94 solvers

Problem

Make a checkerboard matrix (★★★★★)
(copy of Prob. 4) Given an integer n, make an n-by-n matrix made up of alternating ones and zeros as shown below. The a(1...

6 years ago | 0 | 90 solvers

Problem

Sum of elements in a vector (★)
(copy of Prob. 3) Find the sum of all the numbers of the input vector x. Input x = [1 2 3 5] Output y is 11 <> ...

6 years ago | 0 | 142 solvers

Problem

Sum of elements of a vector (★★★)
Given any vector x = [x1, x2, x3, ... xn], compute the sum of its elements. Thus, if x = [ 1 3 -2 5 ], then the sum of its el...

6 years ago | 1 | 87 solvers

Problem

Magnitude of a vector (★★★)
Given a vector x with values [ x1, x2, x3, ..., xn ], compute the magnitude (or length) of the vector which is given by <<htt...

6 years ago | 0 | 82 solvers

Problem

Extract leading non-zero digit (★★★★★)
(Copy of Problem 47) Benford's Law states that the distribution of leading digits is not random. This is probably because man...

6 years ago | 1 | 32 solvers

Problem

Fill a zeros matrix (★★★★★)
(Copy of Problem 830) The aim is to fill an array of all zeros given a numerical value and the index of row and columns for t...

6 years ago | 1 | 38 solvers

Problem

*Prime number check 2 (in construction)
Another way to see if a number is prime is to count the number of factors. For example, the number 4 has 2 factors, [ 2 4 ]...

6 years ago | 0 | 30 solvers

Problem

Median computation (challenge edition)
See easy edition of this problem. However, now you must compute the median of any real-valued vector without using the in-built...

6 years ago | 0 | 40 solvers

Problem

Median computation (easy edition)
Given a vector of values, compute the median. The median is defined as the middle value in a set of *sorted* data. Thus, if ...

6 years ago | 0 | 90 solvers

Problem

Variance computation (easy edition)
Given a vector x with several values, compute the variance, whose formula is given by: <<https://i.imgur.com/Wg95KBE.gif>> ...

6 years ago | 0 | 79 solvers

Problem

Variance computation
Given a vector x with several values, compute the variance, whose formula is given by: <<https://i.imgur.com/Wg95KBE.gif>> ...

6 years ago | 1 | 37 solvers

Problem

Mo money, mo math #2! (adapted from Prob 9 Cody team)
You have a matrix for which each row is a person and the columns represent the number of quarters, dimes, nickels and pennies th...

6 years ago | 0 | 44 solvers

Problem

Approximate functions 1
Compute the following sum for any given x and positive integer n. <<https://i.imgur.com/eUwXdSE.gif>> <> Here m! denote...

6 years ago | 0 | 49 solvers

Problem

Prime number check
One way to see if a number x is prime is to compute the remainders obtained when dividing x by all integers from 2 to √(x). If x...

6 years ago | 1 | 56 solvers

Problem

Function 1
Compute the value of <<https://i.imgur.com/AxKWLmE.gif>> for any given positive x.

6 years ago | 0 | 74 solvers

Problem

Sum of terms in a series 1
Given x and n, compute the following sum: |x|+|x|^(1/2)+|x|^(1/3)+|x|^(1/4)+|x|^(1/5) ... + |x|^(1/n) where ||x|| indica...

6 years ago | 0 | 56 solvers

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...

6 years ago