Find distinct characters in distinct substrings of a string | Java implementation of the approach ; Function to return the count of distinct characters in all the distinct sub - strings of the given string ; To store all the sub - strings ; To store the current sub - string ; To store the characters of the current sub - string ; If current sub - string hasn 't  been stored before ; Insert it into the set ; Update the count of distinct characters ; Driver code
import java . util . HashSet ; class geeks { public static int countTotalDistinct ( String str ) { int cnt = 0 ; HashSet < String > items = new HashSet < > ( ) ; for ( int i = 0 ; i < str . length ( ) ; ++ i ) { String temp = " " ; HashSet < Character > ans = new HashSet < > ( ) ; for ( int j = i ; j < str . length ( ) ; ++ j ) { temp = temp + str . charAt ( j ) ; ans . add ( str . charAt ( j ) ) ; if ( ! items . contains ( temp ) ) { items . add ( temp ) ; cnt += ans . size ( ) ; } } } return cnt ; } public static void main ( String [ ] args ) { String str = " ABCA " ; System . out . println ( countTotalDistinct ( str ) ) ; } }