2144 Leaky Cryptography

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2144 Leaky Cryptography - (2006/04/17 (月) 02:16:56) のソース

**2144 Leaky Cryptography
**問題
http://acm.pku.edu.cn/JudgeOnline/problem?id=2144
**解答例
 import java.util.*;
 public class Main {
     public static void main(String[] args) {
         Scanner sc = new Scanner(System.in);
         int n = sc.nextInt();
         for(int i=0;i<n;i++){
             int[] a = new int[9];
             for(int j=0;j<9;j++){
                 long tmp = sc.nextLong(16);
                 if(tmp>Integer.MAX_VALUE) tmp -= (long)1<<32;
                 a[j] = (int)tmp;
             }
             
             int key = 0;
             for(int j=0;j<32;j++){
                 int[] b = new int[9];
                 for(int k=0;k<9;k++){
                     b[k] = a[k] ^ key;
                 }
                 int b07sum = 0;
                 for(int k=0;k<8;k++) b07sum += b[k];
                 
                 int mask = (1<<j);
                 if((b07sum&mask)!=(b[8]&mask)) key += (1<<j);
             }
             
             System.out.println(Integer.toHexString(key));
         }
     }
 }