For two strings A and B, we define the similarity of the strings to be the length of the longest prefix common to both strings. For example, the similarity of strings “abc” and “abd” is 2, while the similarity of strings “aaa” and “aaab” is 3. Calculate the sum of similarities of a string S with each of it’s suffixes.

StringSimilarity.java

public class StringSimilarity {
	public static int calculate(String s){
		char[]arr=s.toCharArray();
		int length=arr.length;
		int count=length;
		for(int i=1;i<length;i++){
			int len=length-i;
			int j=0;
			for(;j<len;j++)
				if(arr[j]!=arr[j+i]){
					break;
				}
			count+=j;
		}
		return count;
	}
	/*
	public static int calculate(String s){
		int count=s.length();
		for(int i=1;i<s.length();i++){
			count+=similarCount(s,s.substring(i));
		}
		return count;
	}
	private static int similarCount(String s, String sub){
		for(int i=0;i<sub.length();i++)
			if(s.charAt(i)!=sub.charAt(i)) 
				return i;
		return sub.length();
	}*/
   	public static void main(String[] args) {
		Scanner scanner = new Scanner( System.in );
		int n=scanner.nextInt();
		for(int i=0;i<n;i++){
			String s=scanner.next();
			System.out.println(calculate(s));
		}
	}
}

please tell me about this programme error