itertools.product()

・問題

itertools.product()

This tool computes the cartesian product of input iterables. 
It is equivalent to nested for-loops. 
For example, product(A, B) returns the same as ((x,y) for x in A for y in B).

_{Sample Code}

>>> from itertools import product
>>>
>>> print list(product([1,2,3],repeat = 2))
[(1, 1), (1, 2), (1, 3), (2, 1), (2, 2), (2, 3), (3, 1), (3, 2), (3, 3)]
>>>
>>> print list(product([1,2,3],[3,4]))
[(1, 3), (1, 4), (2, 3), (2, 4), (3, 3), (3, 4)]
>>>
>>> A = [[1,2,3],[3,4,5]]
>>> print list(product(*A))
[(1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5), (3, 3), (3, 4), (3, 5)]
>>>
>>> B = [[1,2,3],[3,4,5],[7,8]]
>>> print list(product(*B))
[(1, 3, 7), (1, 3, 8), (1, 4, 7), (1, 4, 8), (1, 5, 7), (1, 5, 8), (2, 3, 7), (2, 3, 8), (2, 4, 7), (2, 4, 8), (2, 5, 7), (2, 5, 8), (3, 3, 7), (3, 3, 8), (3, 4, 7), (3, 4, 8), (3, 5, 7), (3, 5, 8)]

---

Task

You are given a two lists  and . Your task is to compute their cartesian product X.

_Example

A = [1, 2]
B = [3, 4]

AxB = [(1, 3), (1, 4), (2, 3), (2, 4)]

Note:  and  are sorted lists, and the cartesian product's tuples should be output in sorted order.

Input Format

The first line contains the space separated elements of list . 
The second line contains the space separated elements of list .

Both lists have no duplicate integer elements.

Constraints

Output Format

Output the space separated tuples of the cartesian product.

Sample Input

 1 2
 3 4

Sample Output

 (1, 3) (1, 4) (2, 3) (2, 4)

・ソースコード

if __name__ == '__main__':
    from itertools import product
    l1=list(map(int, input().split()))
    l2=list(map(int, input().split()))
    l3=list((product(l1,l2)))
    print (' '.join([str(l3[i])　for i in range (len(l3))]))

・コメント

2行の入力に対してそのコンビネーションを返すプログラム。

問題文のsample codeが分かりやすいので、スラスラ書ける問題。

唯一詰まるポイントは、sample codeと同様にして得られたリストからタプルをjoinで抜き出すことができないので、文字列に変換してから抜き出すことに注意。

・URL

https://www.hackerrank.com/challenges/itertools-product/problem