RepeatedStringMatch.js

// Source : https://leetcode.com/problems/repeated-string-match
// Author : Dean Shi
// Date   : 2017-10-09

/***************************************************************************************
 *
 * Given two strings A and B, find the minimum number of times A has to be
 * repeated such that B is a substring of it. If no such solution, return -1.
 *
 * For example, with A = "abcd" and B = "cdabcdab".
 *
 * Return 3, because by repeating A three times (“abcdabcdabcd”), B is a substring of
 * it; and B is not a substring of A repeated two times ("abcdabcd").
 *
 * Note:
 * The length of A and B will be between 1 and 10000.
 *
 ***************************************************************************************/

/**
 * @param {string} A
 * @param {string} B
 * @return {number}
 */
var repeatedStringMatch = function(A, B) {
    let result = Math.ceil(B.length / A.length)
    const [str1, str2] = [A.repeat(result), A.repeat(result + 1)]

    if (str1.includes(B)) return result
    if (str2.includes(B)) return result + 1

    return -1
};