Code Fights - areSimilar

README.md

Two arrays are called similar if one can be obtained from another by swapping at most one pair of elements in one of the arrays.

Given two arrays a and b, check whether they are similar.

Example

For a = [1, 2, 3] and b = [1, 2, 3], the output should be
areSimilar(a, b) = true.

The arrays are equal, no need to swap any elements.

For a = [1, 2, 3] and b = [2, 1, 3], the output should be
areSimilar(a, b) = true.

We can obtain b from a by swapping 2 and 1 in b.

For a = [1, 2, 2] and b = [2, 1, 1], the output should be
areSimilar(a, b) = false.

Any swap of any two elements either in a or in b won't make a and b equal.

Input/Output

• [time limit] 4000ms (py3)

• [input] array.integer a

  • Array of integers.

  Guaranteed constraints:

  3 ≤ a.length ≤ 105
  1 ≤ a[i] ≤ 1000
  

• [input] array.integer b

  • Array of integers of the same length as a.

  Guaranteed constraints:

  b.length = a.length
  1 ≤ a[i] ≤ 1000
  

• [output] boolean

  • true if a and b are similar, false otherwise.

are_similar.py

from typing import List
from copy import deepcopy


class AreSimilar:
    @classmethod
    def are_similar(cls, a: List[int], b: List[int]):
        if a == b:
            return True
        elif cls._single_swap(a, b):
            return True
        else:
            return False

    @classmethod
    def _same_digits(cls, a: List[int], b: List[int]):
        x, y = deepcopy(a), deepcopy(b)
        x.sort()
        y.sort()
        return x == y

    @classmethod
    def _single_swap(cls, a: List[int], b: List[int]):
        if not cls._same_digits(a, b):
            return False
        differences = 0
        for i in range(len(a)):
            if a[i] != b[i]:
                differences += 1
            if differences > 2:
                break
        return differences <= 2

areSimilar,py

from copy import deepcopy


def areSimilar(a: list, b: list):
    if a == b:
        return True
    elif _single_swap(a, b):
        return True
    else:
        return False

def _same_digits(a: list, b: list):
    x, y = deepcopy(a), deepcopy(b)
    x.sort()
    y.sort()
    return x == y

def _single_swap(a: list, b: list):
    if not _same_digits(a, b):
        return False
    differences = 0
    for i in range(len(a)):
        if a[i] != b[i]:
            differences += 1
        if differences > 2:
            break
    return differences <= 2

test_are_similar.py

import unittest
from are_similar import AreSimilar


class TestAreSimilar(unittest.TestCase):
    def test_1(self):
        a = [1, 2, 3]
        b = [1, 2, 3]
        result = AreSimilar.are_similar(a, b)
        self.assertTrue(result)

    def test_2(self):
        a = [1, 2, 3]
        b = [2, 1, 3]
        result = AreSimilar.are_similar(a, b)
        self.assertTrue(result)

    def test_3(self):
        a = [1, 2, 2]
        b = [2, 1, 1]
        result = AreSimilar.are_similar(a, b)
        self.assertFalse(result)

    def test_4(self):
        a = [1, 1, 4]
        b = [1, 2, 3]
        result = AreSimilar.are_similar(a, b)
        self.assertFalse(result)

    def test_5(self):
        a = [1, 2, 3]
        b = [1, 10, 2]
        result = AreSimilar.are_similar(a, b)
        self.assertFalse(result)

    def test_6(self):
        a = [2, 3, 1]
        b = [1, 3, 2]
        result = AreSimilar.are_similar(a, b)
        self.assertTrue(result)

    def test_7(self):
        a = [2, 3, 9]
        b = [10, 3, 2]
        result = AreSimilar.are_similar(a, b)
        self.assertFalse(result)

    def test_8(self):
        a = [4, 6, 3]
        b = [3, 4, 6]
        result = AreSimilar.are_similar(a, b)
        self.assertFalse(result)

    def test_9(self):
        a = [832, 998, 148, 570, 533, 561, 894, 147, 455, 279]
        b = [832, 998, 148, 570, 533, 561, 455, 147, 894, 279]
        result = AreSimilar.are_similar(a, b)
        self.assertTrue(result)

    def test_10(self):
        a = [832, 998, 148, 570, 533, 561, 894, 147, 455, 279]
        b = [832, 570, 148, 998, 533, 561, 455, 147, 894, 279]
        result = AreSimilar.are_similar(a, b)
        self.assertFalse(result)

if __name__ == '__main__':
    unittest.main()