[leetcode] Valid Anagram

From : https://leetcode.com/problems/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.

public class Solution {
public boolean isAnagram(String s, String t) {
if (s.length() != t.length()) {
return false;
}
int[] m = new int[26];
final char a = 'a';
for (int i = 0, len = s.length(); i < len; ++i) {
++m[s.charAt(i) - a];
--m[t.charAt(i) - a];
}
for (int i = 0; i < 26; ++i) {
if (0 != m[i]) {
return false;
}
}
return true;
}
}