Cfrtjryk

Is this a smart method?

public static ArrayList<Integer> getWordLengths( String s )

{



    String str = " " + s + " ";



    ArrayList<Integer> list = new ArrayList<Integer>();



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

    {

        if ( str.charAt(i) == ' ' )

        {

            for ( int j = i+1; j < str.length() ; j++)

            {

                if ( str.charAt(j) == ' ')

                {

                    list.add( j - i - 1 );

                    j = str.length();

                }

            }

        }

    }

    return list;        

}

Sample output:

System.out.println( getWordLengths("This is really easy")); 



[4, 2, 6, 4]

so it worked.

We are only allowed to use length and charAt from the String class.

Code:

    String s = "This is really easy";



    int count = 0;



    for (int i = 0; i < s.length(); i++) {

        if (s.charAt(i) == ' ') {

            System.out.println("count is " + count);

            count = 0;

        } else {

            count++;

        }

    }

    System.out.println("count is " + count);

Output:

count is 4

count is 2

count is 6

count is 4

Explanation:

keep counting the length of each word till you see a blank. As soon as, you see a blank, write down a length current word and set count to zero and make it ready for new word. At the end, you should write down the length the last word outside of the for loop.

Note: Big o of my code is n , yet your is n^2; therefore, my method is faster than your approach.

//only allowed to use length and charAt from string class

public static ArrayList<Integer> getWordLengths( String s )

{

    String str = s + " ";



    ArrayList<Integer> list = new ArrayList<Integer>();



    int count = 0;



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

    {

        if ( str.charAt(i) == ' ' )

        {

            list.add(count);

            count = 0;   

        }

        else

        {

            count++;

        }

    }

    return list;        

}

Output:

[4, 2, 6, 4]

As long as the length and charAt limitations only apply to string methods and not to use of a List this should be fine. Just because you need to count more than one thing doesn't mean you need more than one loop.

There is a split method for String that will split your string into an array of Strings based on the value you give it.

So in this case you could use spaces:

String arr = s.split(" ");

int result = arr.length;

for(int x = 0; x < arr.length; x++) {

    result[x] = arr[x].length();

}

Since you can only use length and charAt, you could also do it this way, which is faster. list will contain the lengths of each word. prev keeps track of the start of the word you're on, so you can use it to subtract when you find the next space. You have to add 1 to it each time so that it will be on the beginning of the word instead of the space.

ArrayList<Integer> list = new ArrayList<Integer>();

int prev = 0;

for(int x = 0; x <= line.length(); x++) {

    if(x == line.length() || line.charAt(x) == ' ') {

        list.add(x - prev);

        prev = x + 1;

    }

}

Check out the String class API! If you want to look into split more, here are some good examples!

If you aren't allowed to use ArrayList, or if you just think tail recursion is cool, you can do it this way:

public static void main(String args) {



    System.out.println( getWordLengths("This is really easy") ); 

}



public static String getWordLengths( String s )

{

    return "[" + getWordLengthsRecursively(s, 0, 0, 0)  + "]";  

}



public static String getWordLengthsRecursively( String s, int i,  int start, int end )

{

    // Last word 

    if ( s.length() == i)

    {

        return "" + (end - start); 

    }



    // Found a word  

    if ( s.charAt(i) == ' ' )

    {

        return (end - start) + ", " + getWordLengthsRecursively(s, ++i, i, i);

    }



    // Word not found.  Move to next character.

    else

    {

        return getWordLengthsRecursively(s, ++i, start, ++end);

    }

}

Output:

[4, 2, 6, 4]

I like it when I don't have to import anything. Don't you?