Problem: Valid Anagram

Question

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?

Solution

TODO

Code

class Solution {
    public boolean isAnagram(String s, String t) {
        if(s.length() != t.length()) return false;
        
        Map<Character, Integer> charCount = new HashMap();
        for(int i=0; i<s.length(); i++) {
            Character c = s.charAt(i);
            if(!charCount.containsKey(c))
                charCount.put(c, 0);
            int count = charCount.get(c);
            charCount.put(c, count+1);
        }
        
        for(int i=0; i<t.length(); i++) {
            Character c = t.charAt(i);
            if(!charCount.containsKey(c) || charCount.get(c) == 0) return false;
            int count = charCount.get(c);
            charCount.put(c, count-1);
        }
        
        return true;
    }
}

Performance