Check if a string is made up of K alternating characters | Java implementation of the approach ; Function to check if a String is made up of k alternating characters ; Check if all the characters at indices 0 to K - 1 are different ; If that bit is already set in checker , return false ; Otherwise update and continue by setting that bit in the checker ; Driver code
class GFG { static boolean isKAlternating ( String s , int k ) { if ( s . length ( ) < k ) return false ; int checker = 0 ; for ( int i = 0 ; i < k ; i ++ ) { int bitAtIndex = s . charAt ( i ) - ' a ' ; if ( ( checker & ( 1 << bitAtIndex ) ) > 0 ) { return false ; } checker = checker | ( 1 << bitAtIndex ) ; } for ( int i = k ; i < s . length ( ) ; i ++ ) if ( s . charAt ( i - k ) != s . charAt ( i ) ) return false ; return true ; } public static void main ( String [ ] args ) { String str = " acdeac " ; int K = 4 ; if ( isKAlternating ( str , K ) ) System . out . print ( " Yes " + "NEW_LINE"); else System . out . print ( " No " + "NEW_LINE"); } }