Hi guys can someone help me how to solve this please?

Question

1. Given a string, return the first recurring letter of that string. If there are no recurring letters, return “None”.
Input Format
• The input line contains a string
Constraints
• The string length should be bigger than 2
• The string should not contain whitespaces
Sample Input 0
life
Sample Output 0
None
Explanation 0
In thw word life is no recurring letter, so the output should be None

Sample Input 1
statistics
Sample Output 1
t
Explanation 1
The first recurring letter in the string statistics is t

Answer 1

- Read the string
- Use String.length() method to check its length was more than 2 characters
- Iterate through the string using loop
- Use String.indexOf() to check whether there is any <i>-th character with duplicate
- Pass the index + 1 as the second argument for String.indexOf() method in order for it to start looking from a higher index. For example,

i = str.indexOf( str.charAt( i ), i + 1 );
if( i != -1 )
{
// this letter has duplicate.
}

Where <i> is an integer used as loop counter, and <str> was the input String variable.

- When String.indexOf() returns any value greater than -1, you know that character at <i>-th index has a duplicate somewhere.

(Edit)
"statistics" should yield 0 instead cause letter 's' (first character - index 0) has duplicates.

Answer 2

Ipang Thank you very much for your answer :)