LeetCode - Algorithms - 1668. Maximum Repeating Substring

Problem

1668. Maximum Repeating Substring

Java

Brute-force loop

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class Solution {
    private int countByPrefix(String sequence, String word) {
        int maxCount = 0;
        int tempCount = 0;
        int word_len = word.length();
        for (int i = 0; i <= sequence.length() - word_len; i++) {
            String str = sequence.substring(i, i + word_len);
            if (str.equals(word)) {
                tempCount++;
                i += word_len - 1;
            } else {
                tempCount = 0;
            }
            if (tempCount > maxCount)
                maxCount = tempCount;
        }
        return maxCount;
    }

    private int countBySuffix(String sequence, String word) {
        int maxCount = 0;
        int tempCount = 0;
        int word_len = word.length();
        for (int i = sequence.length(); i > word_len - 1; i--) {
            String str = sequence.substring(i - word_len, i);
            if (str.equals(word)) {
                tempCount++;
                i = i - word_len + 1;
            } else {
                tempCount = 0;
            }
            if (tempCount > maxCount)
                maxCount = tempCount;
        }
        return maxCount;
    }
    
    public int maxRepeating(String sequence, String word) {
        int maxCount_prefix = countByPrefix(sequence, word);
        int maxCount_suffix = countBySuffix(sequence, word);
        return maxCount_prefix > maxCount_suffix ? maxCount_prefix : maxCount_suffix;       
    }
}

Submission Detail

  • 212 / 212 test cases passed.
  • Runtime: 1 ms, faster than 82.84% of Java online submissions for Maximum Repeating Substring.
  • Memory Usage: 37.5 MB, less than 50.50% of Java online submissions for Maximum Repeating Substring.

© java short easy to understand

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class Solution {
    public int maxRepeating(String sequence, String word) {
        int count = 0;
        String pat = word;
        while (sequence.contains(pat)) {
            count++;
            pat += word;
        }
        return count;        
    }
}

Submission Detail

  • 212 / 212 test cases passed.
  • Runtime: 1 ms, faster than 82.48% of Java online submissions for Maximum Repeating Substring.
  • Memory Usage: 37.6 MB, less than 50.74% of Java online submissions for Maximum Repeating Substring.