HDOJ 2100 Lovekey

import java.util.Scanner;

public class Main{

public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
String a = sc.next();
String b = sc.next();
char[] A = a.toCharArray();
char[] B = b.toCharArray();
char[] C = twentySixAdd(A, B);
boolean boo = true;
for (char d : C) {
if (boo&&d=='A'||d=='\0') {
continue;
}
System.out.print(d);
boo = false;
}
System.out.println();
}
}
public static char[] twentySixAdd(char[] a,char[] b){
char[] c = new char[(a.length>b.length?a.length:b.length)+1];
char m = 0;

for (int i = c.length-1; i>0; i--) {
if (c[i]=='\0') {
c[i] = 'A';
}
if (i>c.length-(a.length<b.length?a.length:b.length)-1) {
char s = (char)(c[i]+a[i-(c.length-a.length)]+b[i-(c.length-b.length)]-'A'-'A');
if (s>'Z') {
c[i] = (char) (s-'Z'-1+'A');
c[i-1] = 'B';

}else{
c[i] = s;
}
}else {
if (a.length>b.length) {
char s = (char) (c[i]+a[i-(c.length-a.length)]-'A');
if (s>'Z') {
c[i] = (char) (s-'Z'-1+'A');
c[i-1] = 'B';
}else{
c[i] = s;
}
}else {
char s = (char) (c[i]+b[i-(c.length-b.length)]-'A');
if (s>'Z') {
c[i] = (char) (s-'Z'-1+'A');
c[i-1] = 'B';
}else{
c[i] = s;
}
}
}
}
return c;
}
}