Strings and StringBuffer

Question

I have a method that I want to return some path of a string example if I input : xxdrrryy - it should return rrr, I can only return a string of length 3, so I am trying this , but I'm stalked . it must be the occurrence of a letter three times consecutively

public String countTriple(String str) {
    int count = 1;
    char currChar = str.charAt(0);
    for(int i=1; i<str.length(); i++) {
        if(currChar == str.charAt(i)) {
            count++;
            if(count == 3) {
                StringBuilder sb = new StringBuilder("");
                for(int j=0; j<3;j++) {
                    sb.append(currChar);
                }
                return sb.toString();
            }
        }
        else {
            count = 1;
        }
        currChar = str.charAt(i);
    }
    return null; //no triple found
}

Try my answer. It's working. Originally there was a small bug, but its fine now. — Shane Sepac
– Shane Sepac, Commented Dec 23, 2017 at 18:28
what if there are more then one match for example aaabcccdeee did you want just aaa or all aaa, ccc, eee ? — Youcef LAIDANI
– Youcef LAIDANI, Commented Dec 23, 2017 at 18:42
yes did not think of this situation , I was checking for one occurrence but that's a nice suggestion @YCF_L — valik
– valik, Commented Dec 23, 2017 at 19:32

dumbPotato21 · Accepted Answer · 2017-12-23 18:32:42Z

2

Unless you have a specific reason not to, I suggest using a regex.

Something like this should suffice

Pattern p = Pattern.compile("(\\w)\\1\\1");
Matcher m = p.matcher("abbccc");
if(m.find()){
    System.out.println(m.group());
}

Just import java.util.regex.*

answered Dec 23, 2017 at 18:32

dumbPotato21

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2 Comments

valik Over a year ago

yes that works thanks @Frank Underwood , can I get an up vote to remove a ban ?

dumbPotato21 Over a year ago

@valik If it works, I suggest accepting and upvoting it

Ankit Kumar Singh · Accepted Answer · 2017-12-23 18:22:21Z

2

Please update your description it is very difficult to understand what you are trying to say. But as far as I am understanding you want to find out the count of a particular character in a string. Say you input "aabbbcccc" then it should return c has 4 characters or something like that.

If that is the case, then simple traverse over each character in that string and add them inside the HashTable and increase the count everytime the character is found, and return the value you require.

I hope this might help you.

answered Dec 23, 2017 at 18:22

Ankit Kumar Singh

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4 Comments

valik Over a year ago

if u input aabbbcccc it should return bbb because the rule is cccc has four occurrence and it should be maximum of three occurrence and not less @Ankit Kumar Singh

Ankit Kumar Singh Over a year ago

That's an easy task. You just need to add a check for that.

valik Over a year ago

yes I am trying that right now @Ankit Kumar Singh can I get an up vote to remove a ban ?

valik Over a year ago

for some reason it gives no return value @Ankit Kumar Singh

Shane Sepac · Accepted Answer · 2017-12-23 18:23:31Z

2

This code works. Try this:

public static String countTriple(String str) {

    int count = 1;
    char currChar = str.charAt(0);
    for(int i=1; i<str.length(); i++) {
        if(currChar == str.charAt(i)) {
            count++;
            if(count == 3) {
                StringBuilder sb = new StringBuilder("");
                for(int j=0; j<3;j++) {
                    sb.append(currChar);
                }
                return sb.toString();
            }
        }
        else {
            count = 1;
        }
        currChar = str.charAt(i);
    }
    return null; //no triple found
}

answered Dec 23, 2017 at 18:23

Shane Sepac

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