【LeetCode程序员面试金典】面试题 01.04. Palindrome Permutation LCCI

Given a string, write a function to check if it is a permutation of a palin­ drome. A palindrome is a word or phrase that is the same forwards and backwards. A permutation is a rearrangement of letters. The palindrome does not need to be limited to just dictionary words.

Example1:

Input: "tactcoa" Output: true（permutations: "tacocat"、"atcocta", etc.）

来源：力扣（LeetCode） 链接：https://leetcode-cn.com/problems/palindrome-permutation-lcci 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

判断字符出现的次数 奇数次不超过1即可

java实现

class Solution {
    public boolean canPermutePalindrome(String s) {
        int[] map = new int[256];
        int count = 0;
        for (char c : s.toCharArray()) {
            if ((map[c]++ & 1) == 1) {
                count--;
            } else {
                count++;
            }
        }
        return count <= 1;
    }
}