careercup 1.1: unique characters
Implement an algorithm to determine if a string has all unique characters. What if
you can not use additional data structures?
package careercup; public class test1 { /*Implement an algorithm to determine if a string has all unique characters. What if you can not use additional data structures?*/ public static boolean checkUnique(String s) { if(s.length()<1) return true; final int ASC_MAX = 256; boolean[] flags = new boolean[ASC_MAX]; for(int i=0; i<s.length(); i++) { if(flags[ s.charAt(i) ]){ return false; } else { flags[s.charAt(i)] = true; } } return true; } public static boolean checkUniqueInt(String s){ if(s.length()<1) return true; int checker=0; for(int i=0; i<s.length();i++) { if( (checker & (1<< (s.charAt(i)-'a'))) ==1 ) { return false; } else{ checker |= 1<<(s.charAt(i)-'a'); } } return true; } public static void main(String[] args){ String s = "asdfghjkl"; System.out.println( checkUnique(s) ); } }