luogu1965 转圈游戏 (快速幂)

求(m*10^k+x)%n即可

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #define LL long long int
 using namespace std;

 LL rd(){
     LL x=;char c=getchar();int neg=;
     while(c<''||c>''){if(c=='-') neg=-;c=getchar();}
     while(c>=''&&c<='') x=x*+c-'',c=getchar();
     return x*neg;
 }

 LL modp(LL x,int k,int n){
     LL re=;
     while(k){
         if(k&) re=re*x%n;
         k>>=;x=x*x%n;
     }return re;
 }

 int main(){
     int n=rd(),m=rd(),k=rd(),x=rd();
     printf("%d\n",(modp(,k,n)*m+x)%n);
 }