1668. Maximum Repeating Substring #

Problem #

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". 

Constraints:

• 1 <= sequence.length <= 100
• 1 <= word.length <= 100
• sequence and word contains only lowercase English letters.

Problem Summary #

Given a string sequence, if the string formed by repeating string word consecutively k times is a substring of sequence, then the repeating value of word is k. The maximum repeating value of word is the largest repeating value of word in sequence. If word is not a substring of sequence, then the repeating value k is 0. Given strings sequence and word, return the maximum repeating value k.

Solution Ideas #

• Repeatedly concatenate and construct word; each time a new word is constructed, search for it once in sequence. If found, output the number of concatenations; otherwise continue concatenating and constructing until the string length is as long as sequence. If it is still not found in the end, output 0.

Code #

package leetcode

import (
	"strings"
)

func maxRepeating(sequence string, word string) int {
	for i := len(sequence) / len(word); i >= 0; i-- {
		tmp := ""
		for j := 0; j < i; j++ {
			tmp += word
		}
		if strings.Contains(sequence, tmp) {
			return i
		}
	}
	return 0
}