LeetCode242 Valid Anagram

public boolean isAnagram(String s, String t) {
        int lenS = s.length();
        int lenT = t.length();
        if (lenS == 0 && lenT == 0) return true;
        if (lenS == 1 && lenT == 1 && s.equals(t)) return true;
        if (lenS != lenT) return false;
        if (s.equals(t)) return false;
        int[] recordS = new int[26];
        int[] recordT = new int[26];
        for (int i = 0; i < lenS; i++) {
            char c1 = s.charAt(i);
            char c2 = t.charAt(i);
            int index1 = c1 - 'a';
            int index2 = c2 - 'a';
            recordS[index1]++;
            recordT[index2]++;
        }

        for (int i = 0; i < 26; i++)
            if (recordS[i] != recordT[i])
                return false;

        return true;
    }