Java > Warmup-2 > countXX (CodingBat Solution)

Problem:

Count the number of "xx" in the given string. We'll say that overlapping is allowed, so "xxx" contains 2 "xx".

countXX("abcxx") → 1
countXX("xxx") → 2
countXX("xxxx") → 3


Solution:

int countXX(String str) {
  int count = 0;
  for (int i = 0; i < str.length()-1; i++) {
    if (str.substring(i, i+2).equals("xx")) count++;
  }
  return count;
}

// Solution notes: the loop is shortened to end at str.length()-1
// so we can pull out a length 2 substring without going out of bounds.
// Remember to use equals() to compare strings, not ==.

3 comments:

  1. Vinod VBApril 20, 2020 at 6:09 AM

    public int countXX(String str)
    {
    int count=0;
    char[] arr=str.toCharArray();
    for(int i=0;i<arr.length-1;i++)
    {
    if(arr[i]=='x'&&arr[i+1]=='x')
    count++;
    }
    return count;
    }

    ReplyDelete
  2. AnonymousSeptember 18, 2020 at 2:53 AM

    private final int countXX(String word) {
    if(word.length() <= 2 && !word.equals("xx")){
    return 0;
    }
    if(word.charAt(0) == 'x' && word.charAt(1) == 'x'){
    return 1 + countXX(word.substring(1));
    }
    return countXX(word.substring(1));
    }

    ReplyDelete
  3. GularaSeptember 6, 2021 at 3:40 PM

    int countXX(String str) {

    int count = 0;

    for(int i = 0; i < str.length()-1; i++){

    if(str.charAt(i) == 'x' && str.charAt(i+1) == 'x'){
    count++;
    }
    }

    return count;

    }

    ReplyDelete