题目

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.

Follow up:
What if the inputs contain unicode characters? How would you adapt your solution to such case?

答案

class Solution {
    public boolean isAnagram(String s, String t) {
        int[] freq = new int[26];
        int count = 0;
        for(int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            freq[c - 'a']++;
            count++;
        }

        for(int i = 0; i < t.length(); i++) {
            char c = t.charAt(i);
            if(freq[c-'a'] <= 0)
                return false;
            freq[c - 'a']--;
            count--;
        }

        return count == 0;
    }
}