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.

分析：

用array记录每个字符在A中出现的个数，然后再减去B中的字符，如果不够，说明不包含。

 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 == null && B == null) return true;
         if (B == null) return true;

         int[] charCounts = new int[];

         for (int i = ; i < A.length(); i++) {
             charCounts[A.charAt(i)]++;
         }

         for (int i = ; i < B.length(); i++) {
             if (charCounts[B.charAt(i)] == ) {
                 return false;
             }
             charCounts[B.charAt(i)]--;
         }
         return true;
     }
 }