383. Ransom Note

class Solution {
    public boolean canConstruct(String ransomNote, String magazine) {
        int[] count = new int[26];
        for (int i = 0; i < magazine.length(); i++) {
            count[magazine.charAt(i) - 'a']++;
        }

        for (int i = 0; i < ransomNote.length(); i++) {
            char c = ransomNote.charAt(i);
            if (count[c - 'a'] > 0) {
                count[c - 'a']--;
            } else {
                return false;
            }
        }

        return true;
    }
}

Reference

383. Ransom Note