List Comprehensions (Python 3)

• URL : https://www.hackerrank.com/challenges/list-comprehensions/problem

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. 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;. Please use list comprehensions rather than multiple loops, as a learning exercise.

• Example
  • x = 1
  • y = 1
  • z = 2
  • n = 3

All permutations of [i,j,k] are: [[0,0,0],[0,0,1],[0,0,2],[0,1,0],[0,1,1],[0,1,2],[1,0,0],[1,0,1],[1,0,2],[1,1,0],[1,1,1],[1,1,2]].

Print an array of the elements that do not sum to n = 3. [[0,0,0],[0,0,1],[0,0,2],[0,1,0],[0,1,1],[1,0,0],[1,0,1],[1,1,0],[1,1,2]].

• Input Format
  • Four integers x, y, z and n, each on a separate line.
• Constraints
  • Print the list in lexicographic increasing order.

문제풀이

• 무언가 list comprehensions으로 풀어야할것 같지만.. 배움이 아직 짧은듯 싶다.
• i,j,k는 x,y,z보다 숫자가 작거나 같고, 그 원소들로 [i,j,k]의 리스트를 만들면 되니, for문으로 각각 append 시켜주는 코드를 생성하였다.

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

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total_ls = []
ls = []
for i in range(x+1):
    for j in range(y+1):
        for k in range(z+1):
            ls.append(i)
            ls.append(j)
            ls.append(k)
            if sum(ls) != n:
                total_ls.append(ls)
            ls = []

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total_ls

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

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