Codingbat challenge: maxBlock-CodePudding

Given the task

CodePudding user response：

You're not correctly resetting your currentBlock count. You need to reset the currentBlock to 1 if the following character is different from the current one. If not, you need to continue increasing currentBlock:

public int maxBlock(String str) {
  int maxBlock = 0;
  int currentBlock = 1;
  
  if (str.length() < 1) {
    return maxBlock;
  } else {
    maxBlock = 1;
  }
  
  for (int i = 0; i < str.length() - 1; i  ) {
    if (str.charAt(i) ==  str.charAt(i 1)) {
      currentBlock  ;
      if (currentBlock > maxBlock) {
        maxBlock = currentBlock;
      }
    } else {
      currentBlock = 1;
    }
  }
  
  return maxBlock;
}

CodePudding user response：

Although I think @Robby Cornelissen and @Eskandar Abedini's solutions are definitely more viable than mine and closer to the original code, I would like to chip in to offer a different approach by using regex and a bit of coding logic.

The following regex looks for a match where a character reappears 0 or more times. This could be employed with the results() method of the Matcher class to extract the longest match found.

Here is a link to test the regex

https://regex101.com/r/OcMoQ9/1

Code Implementation

List<String> testCase = List.of("hoopla", "abbCCCddBBBxx", "", "xyz", "xxyz", "xyzz", "abbbcbbbxbbbx", "XXBBBbbxx", "XXBBBbbxxXXXX", "XX2222BBBbbXX2222");
Pattern pattern = Pattern.compile("(.)(\\1*)");
Matcher matcher;

for (String s : testCase) {
    matcher = pattern.matcher(s);
    System.out.printf("%s => %d%n", s, matcher
            .results()
            .map(match -> match.group().length())
            .max(Comparator.comparing(Integer::intValue))
            .orElse(0));
}

Link to Test the code

https://www.jdoodle.com/iembed/v0/rH7

Output

hoopla => 2
abbCCCddBBBxx => 3
 => 0
xyz => 1
xxyz => 2
xyzz => 2
abbbcbbbxbbbx => 3
XXBBBbbxx => 3
XXBBBbbxxXXXX => 4
XX2222BBBbbXX2222 => 4

CodePudding user response：

This code is generated by GitHub Copilot plugin for IntelliJ, you need just type int maxBlock then GitHub Copilot generates rest of the code:

private int maxBlock(String s) {
    if (s == null || s.length() == 0) return 0;
    int maxBlocks = 0;
    int currentBlocks = 0;
    char currentChar = s.charAt(0);
    for (int i = 0; i < s.length(); i  ) {
        if (s.charAt(i) == currentChar) {
            currentBlocks  ;
        } else {
            currentBlocks = 1;
            currentChar = s.charAt(i);
        }
        maxBlocks = Math.max(maxBlocks, currentBlocks);
    }
    return maxBlocks;
}

I only added if (s == null || s.length() == 0) return 0; to generated code.