List Comprehensions in Python – Hacker Rank Solution

 

Task
Let’s learn about list comprehensions! You are given three integers X,Y and Z representing the dimensions of a cuboid along with an integer N. You have to print a list of all possible coordinates given by (i,j,k) on a 3D grid where the sum of i+j+k is not equal to N. Here, 0<=i<=X; 0<=j<=Y; 0<=k<=Z

Example

x = 1

y = 1

z = 2

n = 3

Input Format

Four integers x, y, z and n, each on a separate line.

Constraints

Print the list in lexicographic increasing order.

Sample Input 0

1
1
1
2

Sample Output 0

[[0, 0, 0], [0, 0, 1], [0, 1, 0], [1, 0, 0], [1, 1, 1]]

Explanation 0

Concept

You have already used lists in previous hacks. List comprehensions are an elegant way to build a list without having to use different for loops to append values one by one. This example might help.

Example: You are given two integers x and y . You need to find out the ordered pairs ( i , j ) , such that ( i + j ) is not equal to n and print them in lexicographic order.( 0 <= i <= x ) and ( 0 <= j <= y) This is the code if we dont use list comprehensions in Python.

python x = int ( raw_input()) y = int ( raw_input()) n = int ( raw_input()) ar = [] p = 0 for i in range ( x + 1 ) : for j in range( y + 1): if i+j != n: ar.append([]) ar[p] = [ i , j ] p+=1 print ar
Other smaller codes may also exist, but using list comprehensions is always a good option. Code using list comprehensions:

python x = int ( raw_input()) y = int ( raw_input()) n = int ( raw_input()) print [ [ i, j] for i in range( x + 1) for j in range( y + 1) if ( ( i + j ) != n )]

Sample Input 1

2
2
2
2

Sample Output 1

[[0, 0, 0], [0, 0, 1], [0, 1, 0], [0, 1, 2], [0, 2, 1], [0, 2, 2], [1, 0, 0], [1, 0, 2], [1, 1, 1], [1, 1, 2], [1, 2, 0], [1, 2, 1], [1, 2, 2], [2, 0, 1], [2, 0, 2], [2, 1, 0], [2, 1, 1], [2, 1, 2], [2, 2, 0], [2, 2, 1], [2, 2, 2]]

List Comprehensions in Python – Hacker Rank Solution

Code:

if __name__ == '__main__':
    x = int(input())
    y = int(input())
    z = int(input())
    n = int(input())

    print(list([i,j,k] for i in range(x+1) for j in range(y+1) for k in range(z+1)  if i+j+k !=n))

Disclaimer: The above Problem (List Comprehensions in Python – Hacker Rank Solution) is generated by Hackerrank but the Solution is Provided by MultiplexCoder. This tutorial is only for Educational and Learning purposes. Authority if any of the queries regarding this post or website fill the following contact form thank you.
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