/* *266. Palindrome Permutation *2016-6-24 by Mingyang *这个题目很简单的是HashSet来做,遇到一样的,就remove,从没出现的就Add */ public boolean canPermutePalindrome1(String s) { Set<Character> set=new HashSet<Character>(); for(int i=0; i<s.length(); ++i){ if (!set.contains(s.charAt(i))) set.add(s.charAt(i)); else set.remove(s.charAt(i)); } return set.size()==0 || set.size()==1; }