242. Valid Anagram

Problem

Given two strings s and t, return true if t is an anagram of s, and false otherwise.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Solution

两数组相等时，直接遍历两个数组并记录各个字符出现的数量。
一个数组遍历时用做加法，另一个做减法。
如果最后每个字符出现的数量均为0，则返回真。

Code

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