字符串练习题（二）：词语变形

public class Transform {
    public boolean chkTransform(String A, int lena, String B, int lenb) {
        if(A == null || B == null || lena != lenb){
            return false;
        }
         
        char[] chas1 = A.toCharArray();
        char[] chas2 = B.toCharArray();
        int[] map = new int[256];
        for(int i = 0; i < chas1.length; i++){
            map[chas1[i]]++;
        }
        for(int i = 0; i < chas2.length; i++){
            if(map[chas2[i]]-- == 0){
                return false;
            }
        }
        return true;
    }
}