MaximumRepeatingSubstring.php

<?php

namespace App;

/**
 * Maximum Repeating Substring
 *
 * For a string sequence, a string word is k-repeating if word concatenated k times is a substring of sequence. The
 * word's maximum k-repeating value is the highest value k where word is k-repeating in sequence. If word is not
 * a substring of sequence, word's maximum k-repeating value is 0. Given strings sequence and word, return the maximum
 * k-repeating value of word in sequence.
 *
 * Example 1:
 * Input: sequence = "ababc", word = "ab"
 * Output: 2
 * Explanation: "abab" is a substring in "ababc".
 *
 * Example 2:
 * Input: sequence = "ababc", word = "ba"
 * Output: 1
 * Explanation: "ba" is a substring in "ababc". "baba" is not a substring in "ababc".
 *
 * Example 3:
 * Input: sequence = "ababc", word = "ac"
 * Output: 0
 * Explanation: "ac" is not a substring in "ababc".
 *
 * https://leetcode.com/problems/maximum-repeating-substring
 */
class MaximumRepeatingSubstring
{
    /**
     * @param string $sequence
     * @param string $word
     * @return int
     */
    public function maxRepeating(string $sequence, string $word): int
    {
        $max = 0;
        $i = 1;
        while (str_contains($sequence, str_repeat($word, $i))) {
            $max = $i;
            $i++;
        }
        return $max;
    }
}