interview-questions

Compare Strings

Compare two strings A and B, determine whether A contains all of the caracters in B. The characters in string A and B are all Upper Case letters.

Example

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

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

Note

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

Solution

We use count array to record every occured character in A and B. Then we just compare the count array.

// Language: JAVA
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) {
        int[] count = new int[26];
        for (int i = 0; i < B.length(); i++) {
            count[B.charAt(i)-'A'] += 1;
        }
        for (int i = 0; i < A.length(); i++) {
            count[A.charAt(i)-'A'] -= 1;
        }
        for (int i = 0; i < 26; i++) {
            if (count[i] > 0) {
                return false;
            }
        }
        return true;
    }
}