hdu 1576 A/B

原题链接：hdu 1576 A/B

同样是用扩展的欧几里得算法。A = 9973k+n = xB，从而转化为：xB-9973k=n求解x即可。

具体扩展欧几里得算法请参考：hdu 2669 Romantic

代码如下：

 1 #include <cstdio>
 2 #include <cstdlib>
 3 #include <iostream>
 4 #include <cstring>
 5 #define     MOD 9973
 6 using namespace std;
 7 typedef long long LL;
 8 void exgcd(LL a, LL b, LL &d, LL &x, LL&y)
 9 {
10     if( b == 0 )
11     {
12         d = a;
13         x = 1;
14         y = 0;
15     }
16     else
17     {
18         exgcd(b, a%b, d, x, y);
19         int t = x;
20         x = y;
21         y = t - (a/b)*y;
22     }
23 }
24 int main(int argc, char *argv[])
25 {
26     int T;
27     scanf ( "%d", &T );
28     int n, a, b;
29     LL d, x, y;
30     while( T-- )
31     {
32         scanf("%d%d", &n, &b);   
33         a = MOD;
34         exgcd(a, b, d, x, y);
35         y = (y%MOD)*(n/d)%MOD;
36         y = (y+MOD)%MOD;
37         cout<<y<<endl;
38     }
39 }

 

posted @ 2014-10-06 14:35  jostree  阅读(261)  评论(0)    收藏  举报