Compare two strings A and B, determine whether A contains all of the characters in B.

The characters in string A and B are all Upper Case letters.

一个Hashtable的题，用Hashtable统计A中各个字符出现的次数，当B中出现的时候就减去相应的次数，如果次数为负，说明B中出现了A中没有的字符

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public boolean compareStrings(String A, String B) {
    int[] chars = new int[26];
    for (int i = 0; i < A.length(); i++) {
        chars[A.charAt(i) - 'A']++;
    }
    for (int i = 0; i < B.length(); i++) {
        chars[B.charAt(i) - 'A']--;
        if (chars[B.charAt(i) - 'A'] < 0)
            return false;
    }
    return true;
}