NumberOfRectangles.php

<?php

namespace App;

/**
 * Number Of Rectangles That Can Form The Largest Square
 *
 * You are given an array rectangles where rectangles[i] = [l_i, w_i] represents the ith rectangle of length l_i and
 * width w_i. You can cut the i-th rectangle to form a square with a side length of k if both k <= l_i and k <= w_i.
 * For example, if you have a rectangle [4,6], you can cut it to get a square with a side length of at most 4.
 * Let maxLen be the side length of the largest square you can obtain from any of the given rectangles.
 * Return the number of rectangles that can make a square with a side length of maxLen.
 *
 * Example 1:
 * Input: rectangles = [[5,8],[3,9],[5,12],[16,5]]
 * Output: 3
 * Explanation: The largest squares you can get from each rectangle are of lengths [5,3,5,5].
 * The largest possible square is of length 5, and you can get it out of 3 rectangles.
 *
 * https://leetcode.com/problems/number-of-rectangles-that-can-form-the-largest-square
 */
class NumberOfRectangles
{
    /**
     * @param array<array-key, int> $rectangles
     * @return int
     */
    public function countGoodRectangles(array $rectangles): int
    {
        $largestSquares = [];
        $maxSquare = PHP_INT_MIN;
        /** @var array<array-key, int> $rectangle */
        foreach ($rectangles as $rectangle) {
            $largestPossibleSquare = min($rectangle[0], $rectangle[1]);
            $largestSquares[] = $largestPossibleSquare;
            if ($maxSquare < $largestPossibleSquare) {
                $maxSquare = $largestPossibleSquare;
            }
        }

        $goodRectangles = 0;
        foreach ($largestSquares as $largestSquare) {
            if ($largestSquare === $maxSquare) {
                $goodRectangles++;
            }
        }
        return $goodRectangles;
    }
}