扩展中国剩余定理

 

P4777 【模板】扩展中国剩余定理（EXCRT）

 

 1 #include <cstdio>
 2 #include <cstdlib>
 3 #include <cmath>
 4 #include <cstring>
 5 #include <algorithm>
 6 using namespace std;
 7 #define ll long long
 8 //#define int128 __int128
 9 
10 //typedef ll type;
11 typedef __int128 type;
12 
13 ll c,x,y,_a2,_b2;
14 type a1,b1,a2,b2,a3;
15 
16 void gcd(type a,type b)
17 {
18     if (b==0)
19     {
20         if ((b2-b1)%a!=0)
21         {
22             printf("-1\n");
23             exit(0);
24         }
25         c=a;
26         x=(b2-b1)/a;
27         y=0;
28     }
29     else
30     {
31         gcd(b,a%b);
32         type z;
33         z=x;
34         x=y;
35         y=z-a/b*y;
36     }
37 }
38 
39 int main()
40 {
41     int n,i;
42     a1=1,b1=0;
43     scanf("%d",&n);
44     for (i=1;i<=n;i++)
45     {
46         scanf("%lld%lld",&_a2,&_b2);    ///read __int128 can't use cin
47         a2=_a2,b2=_b2;
48         if (a2>a1)
49             swap(a1,a2),swap(b1,b2);
50         gcd(a1,a2);
51 
52         a3=a1/c*a2;
53         b1=((a1*x+b1)%a3+a3)%a3;
54         a1=a3;
55     }
56     printf("%lld",(ll)b1);
57     return 0;
58 }