hdu 1111 Secret Code

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 int a[110];
 7 __int64 n;
 8 int x1,y1,b1,b2;
 9 int t1;
10 bool flag;
11 
12 void dfs(int cnt)
13 {
14     if(cnt>100) return;
15     if(x1==0&&y1==0)
16     {
17         flag=true;
18         t1=cnt;
19         return;
20     }
21     for(int i=0; i*i<=n; i++)
22     {
23         if(flag) return;
24         __int64  xx=(x1-i)*b1+y1*b2;
25         __int64  yy=y1*b1-(x1-i)*b2;
26         if(xx%n==0&&yy%n==0)
27         {
28             x1=xx/n;
29             y1=yy/n;
30             a[cnt]=i;
31             dfs(cnt+1);
32         }
33     }
34 }
35 
36 int main()
37 {
38     int t;
39     scanf("%d",&t);
40     while(t--)
41     {
42         scanf("%d%d%d%d",&x1,&y1,&b1,&b2);
43         n=b1*b1+b2*b2;
44         flag=false;
45         dfs(0);
46         if(!flag)
47         {
48             printf("The code cannot be decrypted.\n");
49         }
50         else
51         {
52             printf("%d",a[t1-1]);
53             for(int i=t1-2; i>=0; i--)
54             {
55                 printf(",%d",a[i]);
56             }
57             printf("\n");
58         }
59     }
60     return 0;
61 }