POJ 2891 Strange Way to Express Integers(中国剩余定理)

题目链接

虽然我不懂...

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <map>
 4 #include <cmath>
 5 using namespace std;
 6 #define LL __int64
 7 LL p[1001],o[1001];
 8 LL x,y;
 9 LL ext_eulid(LL a,LL b)
10 {
11     LL t,d;
12     if(b == 0)
13     {
14         x = 1;
15         y = 0;
16         return a;
17     }
18     d = ext_eulid(b,a%b);
19     t = x;
20     x = y;
21     y = t - (a/b)*y;
22     return d;
23 }
24 LL gcd(LL a,LL b)
25 {
26     return b == 0?a:gcd(b,a%b);
27 }
28 int main()
29 {
30     int i,n,z;
31     LL p1,o1,d,c,mod;
32     while(scanf("%d",&n)!=EOF)
33     {
34         for(i = 0;i < n;i ++)
35         {
36             scanf("%I64d%I64d",&p[i],&o[i]);
37         }
38         p1 = p[0];
39         o1 = o[0];
40         z = 1;
41         for(i = 1;i < n&&z;i ++)
42         {
43             d = ext_eulid(p1,p[i]);
44             c = o[i] - o1;
45             if(c%d) z = 0;
46             mod = p[i]/d;
47             x = ((c/d*x)%mod+mod)%mod;
48             o1 = p1*x + o1;
49             p1 = p1*mod;
50         }
51         if(!z)
52         printf("-1\n");
53         else
54         printf("%I64d\n",o1);
55     }
56     return 0;
57 }

 

posted @ 2013-07-24 13:39  Naix_x  阅读(178)  评论(2)  编辑  收藏  举报