leetcode:242. Valid Anagram

Given two strings s and t, write a function to determine if t is an anagram of s.
For example,

s = "anagram", t = "nagaram", return true.
s = "rat", t = "car", return false.

Note:You may assume the string contains only lowercase alphabets.

public class Solution {
    public boolean isAnagram(String s, String t) {
        int[] map = new int[26];
        char[] cs = s.toCharArray();
        for(char c : cs) {
            int x = c - 'a';
            map[x] += 1;
        }      
        cs = t.toCharArray();
        for(char c : cs) {
            int x = c - 'a';
            if(map[x] == 0) {
                return false;
            }
            map[x] -= 1;
        }
        for(int x : map) {
            if(x != 0) {
                return false;
            }
        }
        return true;
    }
}
//是否字母顺序不一样，用一个哈希表记录其中一个字符串的每一个字符及
//出现的次数。用另一个字符串的字符当作key获取value判断是否存在。