usaco 1.43Arithmetic Progressions
直接枚举a1和d。
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1 /* 2 ID: your_id_here 3 PROG: ariprog 4 LANG: C++ 5 */ 6 #include <iostream> 7 #include<cstdio> 8 #include<cstring> 9 using namespace std; 10 int f[200000]; 11 int main() 12 { 13 freopen("ariprog.in","r",stdin); 14 freopen("ariprog.out","w",stdout); 15 int i,j,n,m,k,a,d,flag; 16 f[0] = 1; 17 int ff = 0; 18 cin>>n>>m; 19 for(i = 0 ; i <= m ; i++) 20 for(j = 1; j <= m ; j++) 21 f[i*i+j*j] = 1; 22 for(d = 1 ; d<=2*m*m ; d++) 23 for(a = 0; ; a++) 24 { 25 if(a+(n-1)*d>2*m*m) 26 break; 27 flag = 1; 28 for(i = 0; i < n ; i++) 29 { 30 if(!f[a+i*d]) 31 { 32 flag = 0; 33 break; 34 } 35 } 36 if(flag) 37 { 38 ff = 1; 39 cout<<a<<" "<<d<<endl; 40 } 41 } 42 if(!ff) 43 cout<<"NONE\n"; 44 fclose(stdin); 45 fclose(stdout); 46 return 0; 47 }