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# Itertools

{% embed url="<https://www.hackerrank.com/domains/python?badge_type=python&filters%5Bsubdomains%5D%5B%5D=py-itertools>" %}

## itertools.product()

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2FORGHY52dDcqG6zl9QdOk%2Fimage.png?alt=media&amp;token=57be65e2-e2dd-49b8-b329-208b2c014e5f" alt=""><figcaption></figcaption></figure>

{% code lineNumbers="true" %}

```python
from itertools import product

A = map(int, input().split())
B = map(int, input().split())

print(" ".join(map(str, product(A, B))))
```

{% endcode %}

***

## itertools.permutations()

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2FFekgggd2Q20HT4UJtDj7%2Fimage.png?alt=media&amp;token=3a89adac-e264-4809-9270-c428ad3bfabf" alt=""><figcaption></figcaption></figure>

```python
from itertools import permutations

s, k = input().split()

print("\n".join(sorted(map("".join, permutations(s, int(k))))))
```

***

## itertools.combinations()

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2FKIs3s9uTAgIakAMKHiDp%2Fimage.png?alt=media&amp;token=b42a72f5-05a3-4115-81b5-9adf5d06adf2" alt=""><figcaption></figcaption></figure>

```python
from itertools import combinations

s, k = input().split()

for i in range(int(k)):
    print("\n".join(sorted("".join(sorted(each)) for each in combinations(s, i + 1))))
```

***

## itertools.combinations\_with\_replacement()

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2FZ7llA2zeZcAVdALZrqmB%2Fimage.png?alt=media&amp;token=470bd8b8-63f1-4858-a26b-9e14f9c59e73" alt=""><figcaption></figcaption></figure>

```python
from itertools import combinations_with_replacement

s, k = input().split()

print("\n".join(sorted("".join(sorted(each)) for each in combinations_with_replacement(s, int(k)))))
```

***

## Compress The String!

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2Fc6OuUkzYEU77KoeHY89C%2Fimage.png?alt=media&amp;token=1c3e53a6-b6fe-4d8a-a5f4-f6e631e6427d" alt=""><figcaption></figcaption></figure>

```python
from itertools import groupby

s = input()

print(" ".join(str((len(list(group)), int(value))) for value, group in groupby(s)))
```

***

## Iterables and Iterators

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2FsHhLr8ayUcosw9t4JdXB%2Fimage.png?alt=media&amp;token=b36e9f22-110c-4d07-bafc-dd70dd059f8e" alt=""><figcaption></figcaption></figure>

```python
from itertools import combinations

n = int(input())
letters = input().split()
k = int(input())

combos = list(combinations(letters, k))
print(len(list(each for each in combos if "a" in each)) / len(combos))
```

***

## Maximize It!

<figure><img src="https://3452970062-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhMewGT4PbQ5e1zQPC4Ko%2Fuploads%2FaWJJCzZFZcVZxtLTrp9I%2Fimage.png?alt=media&amp;token=157c8473-4f40-4d9f-a73c-064a0ff0307b" alt=""><figcaption></figcaption></figure>

```python
from itertools import product

k, m = map(int, input().split())

arr = [list(map(lambda x: pow(int(x), 2), input().split()[1:])) for _ in range(k)]

print(max(map(lambda x: sum(x) % m, product(*arr))))
```