RemoveOneElementToMakeArrayStrictlyIncreasing.php

<?php

namespace App;

/**
 * Remove One Element to Make the Array Strictly Increasing
 *
 * Given a 0-indexed integer array nums, return true if it can be made strictly increasing after removing exactly one
 * element, or false otherwise. If the array is already strictly increasing, return true. The array nums is strictly
 * increasing if nums[i - 1] < nums[i] for each index (1 <= i < nums.length).
 *
 * Example 1:
 * Input: nums = [1,2,10,5,7]
 * Output: true
 * Explanation: By removing 10 at index 2 from nums, it becomes [1,2,5,7].
 * [1,2,5,7] is strictly increasing, so return true.
 *
 * Example 2:
 * Input: nums = [2,3,1,2]
 * Output: false
 * Explanation:
 * [3,1,2] is the result of removing the element at index 0.
 * [2,1,2] is the result of removing the element at index 1.
 * [2,3,2] is the result of removing the element at index 2.
 * [2,3,1] is the result of removing the element at index 3.
 * No resulting array is strictly increasing, so return false.
 *
 * Example 3:
 * Input: nums = [1,1,1]
 * Output: false
 * Explanation: The result of removing any element is [1,1].
 * [1,1] is not strictly increasing, so return false.
 *
 * https://leetcode.com/problems/remove-one-element-to-make-the-array-strictly-increasing
 */
class RemoveOneElementToMakeArrayStrictlyIncreasing
{
    /**
     * @param int[] $nums
     * @return bool
     */
    public function canBeIncreasing(array $nums): bool
    {
        $count = count($nums);
        $removed = false;
        for ($i = 1; $i < $count; $i++) {
            if ($nums[$i - 1] >= $nums[$i]) {
                if ($removed) {
                    return false;
                }
                $removed = true;
                if ($i > 1 && $nums[$i - 2] >= $nums[$i]) {
                    $nums[$i] = $nums[$i - 1];
                }
            }
        }
        return true;
    }
}