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.

方法一

class Solution {
public:
    bool isAnagram(string s, string t) {
        if(s.size()!=t.size()){
            return false;
        }
        int b[26]={};
        for(int i=0;i<s.size();i++){
            b[s[i]-'a']++;
        }
        for(int i=0;i<t.size();i++){
            if((--b[t[i]-'a'])<0){
                return false;
            }
        }
        return true;
    }
};

方法二

class Solution {
public:
    bool isAnagram(string s, string t) {
        if (s.size() != t.size())
            return false;
        unordered_map<char, int> mapa;
        for (char& ch : s)
            mapa[ch]++;
        for (char& ch : t)
            mapa[ch]--;
        for (auto it = mapa.begin(); it != mapa.end(); it++)
            if ((*it).second != 0)
                return false;
        return true;
    }
};

方法三

public class Solution {  
    public boolean isAnagram(String s, String t) {  
        char[] sArr = s.toCharArray();  
        char[] tArr = t.toCharArray();  

        Arrays.sort(sArr);  
        Arrays.sort(tArr);  

        return String.valueOf(sArr).equals(String.valueOf(tArr));  
    }  
}