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Junqi Zhang


Last seen: 3 months ago
25 total contributions since 2020

Junqi Zhang's Badges

  • Project Euler I
  • Solver

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Put m balls into n boxes
Can you find all the cases where, if I put 3 balls into 2 boxes the case is 1 1 1 1 1 2 1...

4 months 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...

4 months ago

Solved


Edges of a n-dimensional Hypercube
Return the number of edges on an <http://en.wikipedia.org/wiki/Hypercube _n_-dimensional hypercube> (with an integer n &ge; 0). ...

4 months ago

Solved


Dots in a Sphere
Return how many integer grid points there are inside a 3D sphere of radius _r_ centred at (0,0,0) (including points on the edge)...

4 months ago

Solved


Enlarge array
Given an m-by-n numeric array (A) and a 1-by-2 vector (sz) indicating the dimensions [p q] to enlarge each element, return an (m...

4 months ago

Solved


frame of the matrix
Given the matrix M, return M without the external frame.

4 months ago

Solved


subtract central cross
Given an n-by-n square matrix, where n is an odd number, return the matrix without the central row and the central column.

4 months ago

Solved


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...

4 months ago

Solved


Decimation
When dealing to the Roman Army, the term decimate meant that the entire unit would be broken up into groups of ten soldiers, and...

4 months ago

Solved


Linear system of equations
Solve the system of equations in three variables.

4 months ago

Solved


System of equations
Find a solution to a system of equations represented by a |n| by |n+1| matrix. For instance, [ 2 0 4; => 2*x = 4 ...

4 months ago

Solved


Column norms of a matrix
Given a matrix M, return a vector y such that for each k y(k)=norm(M(:,k)) (y(k) is the Euclidean norm of the k-th col...

4 months ago

Solved


Sherlock Holmes: The Spy Problem
A guest at a party is a spy if this person is not known by any other guest, but knows all of them. There is at most one spy at a...

4 months ago

Solved


matrix zigzag
Unfold a 2-D matrix to a 1-D array in zig-zag order, e.g., for matrix [ 1 2 3 ; 4 5 6 ; 7 8 9 ] the resulting 1-...

4 months ago

Solved


Project Euler: Problem 4, Palindromic numbers
A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ...

4 months ago

Solved


Project Euler: Problem 10, Sum of Primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

4 months ago

Solved


Project Euler: Problem 9, Pythagorean numbers
A Pythagorean triplet is a set of three natural numbers, a b c, for which, a^2 + b^2 = c^2 For example, 3^2 + 4^2 =...

4 months ago

Solved


Project Euler: Problem 8, Find largest product in a large string of numbers
Find the greatest product of five consecutive digits in an n-digit number. 73167176531330624919225119674426574742355349194934...

4 months ago

Solved


Project Euler: Problem 7, Nth prime
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13. What is the Nth prime nu...

4 months ago

Solved


Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

4 months ago

Solved


Project Euler: Problem 5, Smallest multiple
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

4 months ago

Solved


Project Euler: Problem 3, Largest prime factor
The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number being input, input might be ui...

4 months ago

Solved


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.

4 months ago

Solved


Project Euler: Problem 2, Sum of even Fibonacci
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 te...

4 months ago

Solved


Project Euler: Problem 1, Multiples of 3 and 5
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23...

4 months ago