Remove extra characters from front of the current substring
while ( true ) { if ( s . charAt ( st ) >= 65 && s . charAt ( st ) <= 90 && caps [ s . charAt ( st ) - ' A ' ] > 1 ) { caps [ s . charAt ( st ) - ' A ' ] -- ; st ++ ; } else if ( s . charAt ( st ) >= 97 && s . charAt ( st ) <= 122 && small [ s . charAt ( st ) - ' a ' ] > 1 ) { small [ s . charAt ( st ) - ' a ' ] -- ; st ++ ; } else break ; }