Compare Strings

LintCode-55.Compare Strings

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.

Notice: The characters of B in A are not necessary continuous or ordered.

Example:

For A = "ABCD", B = "ACD", return true.

For A = "ABCD", B = "AABC", return false.

This problem is similar to Two Strings Are Anagrams.

public class Solution {
    /**
     * @param A : A string includes Upper Case letters
     * @param B : A string includes Upper Case letter
     * @return :  if string A contains all of the characters in B return true else return false
     */
    public boolean compareStrings(String A, String B) {
        if (A == null || B == null) {
            return false;
        }
        
        if (A.length() < B.length()) {
            return false;
        }
        
        int[] charCount = new int[256];
        for (int i = 0; i < A.length(); i++) {
            charCount[A.charAt(i)]++;
        }
        
        for (int i = 0; i < B.length(); i++) {
            charCount[B.charAt(i)]--;
            
            if (charCount[B.charAt(i)] < 0) {
                return false;
            }
        }
        
        return true;
    }
}

Hope this helps,
Michael