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# Cheng Du

83 total contributions since 2019

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Find nth maximum
Find nth maximum in a vector of integer numbers. Return NaN if no such number exists. x = [2 6 4 9 -10 3 1 5 -10]; So ...

8 months ago

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Create an index-powered vector
Given a input vector x, return y as index-powered vector as shown below. Example x = [2 3 6 9] then y should be [...

8 months ago

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Check if sorted
Check if sorted. Example: Input x = [1 2 0] Output y is 0

8 months ago

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Number of digits in an integer
Specifies how many digits in a given integer. Example: in=100 ==> out=3

8 months ago

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The sum of the numbers in the vector
eg. [1,2,3]---->SUM=6

8 months ago

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Back to basics 21 - Matrix replicating
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, generate an output matrix that consists o...

8 months ago

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Check if number exists in vector
Return 1 if number _a_ exists in vector _b_ otherwise return 0. a = 3; b = [1,2,4]; Returns 0. a = 3; b = [1,...

8 months ago

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Magic is simple (for beginners)
Determine for a magic square of order n, the magic sum m. For example m=15 for a magic square of order 3.

8 months ago

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Find the sum of the elements in the "second" diagonal
Find the sum of the elements in the diagonal that starts at the top-right corner and ends at the bottom-left corner.

8 months ago

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Return area of square
Side of square=input=a Area=output=b

8 months ago

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Sum of odd numbers in a matrix
Find the sum of all the odd numbers in a matrix. Example x = [2 3 5 7 1 4 11] y = 27

8 months ago

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Back to basics 11 - Max Integer
Covering some basic topics I haven't seen elsewhere on Cody. Return the largest positive integer MATLAB can handle.

8 months ago

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Sum all integers from 1 to 2^n
Given the number x, y must be the summation of all integers from 1 to 2^x. For instance if x=2 then y must be 1+2+3+4=10.

8 months ago

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Flipping
Write code that can reverse the vector without using any sort of loop. Example Given the input vector A = [ 1 2 3 4 5...

8 months ago

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Element by element multiplication of two vectors
Given two input vectors, return the element-by-element product. Example A = [1 2 3] B = [7 3 1] The answer should be...

8 months ago

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Divide by 4
Given the variable x as your input, divide it by four and put the result in y.

8 months ago

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Find the 9's Complement
Find the 9's complement of the given number. An example of how this works is <http://electrical4u.com/9s-complement-and-10s-c...

8 months ago

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Roll the Dice!
*Description* Return two random integers between 1 and 6, inclusive, to simulate rolling 2 dice. *Example* [x1,x2] =...

8 months ago

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Swap the input arguments
Write a two-input, two-output function that swaps its two input arguments. For example: [q,r] = swap(5,10) returns q = ...

8 months ago

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Given a 4x4 matrix, swap the two middle columns
If a = [1 2 3 4; 1 2 3 4; 1 2 3 4; 1 2 3 4]; then the result is ans = 1 3 2 4 1 3 2...

8 months ago

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Area of a circle
Find the value for area of the circle if diameter is given

8 months ago

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Reverse the vector
Reverse the vector elements. Example: Input x = [1,2,3,4,5,6,7,8,9] Output y = [9,8,7,6,5,4,3,2,1]

8 months ago

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Half?
If you toss an even number (x) of coins, what is the probability (y) of 50% head and 50% tail?

8 months ago

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Negative Infinity
Round the given array a towards negative infinity.

8 months ago

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Y=X
Given an input variable x, output a variable y that is equal in value to x. Example: Input x = 1 Output y is 1 Inp...

8 months ago

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Sum of series III
What is the sum of the following sequence: Σ(2k-1)^3 for k=1...n for different n?

8 months ago

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surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

8 months ago

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Weighted average
Given two lists of numbers, determine the weighted average. Example [1 2 3] and [10 15 20] should result in 33.333...

8 months ago

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Array of Ones
Create a 100 X 100 array of ones.

8 months ago

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Find a Pythagorean triple
Given four different positive numbers, a, b, c and d, provided in increasing order: a < b < c < d, find if any three of them com...

8 months ago