【HDU1573】X问题

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<ctime>
 7 #include<algorithm>
 8 using namespace std;
 9 int T,n,s,M,ans,flag,a[15],m[15];
10 inline int read()
11 {
12     int x=0,f=1;  char ch=getchar();
13     while(!isdigit(ch))  {if(ch==‘-‘)  f=-1;  ch=getchar();}
14     while(isdigit(ch))  {x=x*10+ch-‘0‘;  ch=getchar();}
15     return x*f;
16 }
17 void exgcd(int a,int b,int &g,int &x,int &y)
18 {
19     if(b==0)  {x=1; y=0; g=a; return;}
20     exgcd(b,a%b,g,x,y);
21     int t=x;x=y;y=t-a/b*y;
22 }
23 void China()
24 {
25     int A=a[1],k,y;  M=m[1];
26     for(int i=2;i<=n;i++)
27     {
28         int da=a[i]-A,g;
29         exgcd(M,m[i],g,k,y);
30         if(da%g)  {flag=1; return;}
31         int t=m[i]/g;
32         k*=da/g;
33         k=(k+t)%t;
34         A+=k*M;
35         M=M*m[i]/g;
36         A=(A+M)%M;
37     }
38     ans=A;
39 }
40 int main()
41 {
42     freopen("cin.in","r",stdin);
43     freopen("cout.out","w",stdout);
44     T=read();
45     while(T--)
46     {
47         s=read();  n=read();  flag=0;
48         for(int i=1;i<=n;i++)  m[i]=read();
49         for(int i=1;i<=n;i++)  a[i]=read();
50         China();
51         if(ans>s||flag)  {printf("0\n");  continue;}
52         int sum=(s-ans)/M+1;
53         if(ans==0)  sum--;
54         printf("%d\n",sum);
55     }
56     return 0;
57 }