1460. Make Two Arrays Equal by Reversing Subarrays

1460. Make Two Arrays Equal by Reversing Subarrays

Easy

You are given two integer arrays of equal length target and arr. In one step, you can select any non-empty subarray of arr and reverse it. You are allowed to make any number of steps.

Return true if you can make arr equal to target or false otherwise.

Example 1:

• Input: target = [1,2,3,4], arr = [2,4,1,3]
• Output: true
• Explanation: You can follow the next steps to convert arr to target:
  1. Reverse subarray [2,4,1], arr becomes [1,4,2,3]
  2. Reverse subarray [4,2], arr becomes [1,2,4,3]
  3. Reverse subarray [4,3], arr becomes [1,2,3,4]
  4. There are multiple ways to convert arr to target, this is not the only way to do so.

Example 2:

• Input: target = [7], arr = [7]
• Output: true
• Explanation: arr is equal to target without any reverses.

Example 3:

• Input: target = [3,7,9], arr = [3,7,11]
• Output: false
• Explanation: arr does not have value 9 and it can never be converted to target.

Constraints:

• target.length == arr.length
• 1 <= target.length <= 1000
• 1 <= target[i] <= 1000
• 1 <= arr[i] <= 1000

Hint:

1. Each element of target should have a corresponding element in arr, and if it doesn't have a corresponding element, return false.
2. To solve it easily you can sort the two arrays and check if they are equal.

Solution:

To solve this problem, we can follow these steps:

1. Check if both arrays have the same elements with the same frequency. If they do, it means one array can be transformed into the other by reversing subarrays. Sorting both arrays and comparing them is an easy way to achieve this.

Let's implement this solution in PHP: 1460. Make Two Arrays Equal by Reversing Subarrays

<?php
function canBeEqual($target, $arr) {
    // Sort both arrays
    sort($target);
    sort($arr);

    // Compare the sorted arrays
    return $target == $arr;
}

// Test cases
$target1 = [1, 2, 3, 4];
$arr1 = [2, 4, 1, 3];
echo canBeEqual($target1, $arr1) ? 'true' : 'false'; // Output: true

$target2 = [7];
$arr2 = [7];
echo canBeEqual($target2, $arr2) ? 'true' : 'false'; // Output: true

$target3 = [3, 7, 9];
$arr3 = [3, 7, 11];
echo canBeEqual($target3, $arr3) ? 'true' : 'false'; // Output: false
?>

Explanation:

1. Sorting Arrays: By sorting both target and arr, we can ensure that if they have the same elements with the same frequencies, they will become identical after sorting.
2. Comparing Sorted Arrays: If the sorted version of target is equal to the sorted version of arr, it means that arr can be transformed into target by reversing subarrays, as the elements and their frequencies match.

Key Points:

• Sorting: This step ensures that we can compare the elements in both arrays directly.
• Comparison: After sorting, a direct comparison (==) is sufficient to check if both arrays can be made equal through subarray reversals.

This solution leverages the properties of sorting and the comparison of arrays in PHP, making it both simple and efficient.

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