a^b 大数

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define Mod 99991using namespace std;long long int ans,x,y;void fun(long long int n){if(n==0){ans=1;return;}if(n==1){ans=x%Mod;return;}fun(n>>1);                //二分 ans=((ans%Mod)*(ans%Mod)%Mod);if(n%2!=0)              //n为奇数时需要再*x {ans=((ans%Mod)*(x%Mod))%Mod;return;} return; }int main(){int t;scanf("%d",&t);while(t--){scanf("%lld %lld",&x,&y);fun(y);printf("%lld\n",ans);}return 0;}//当b为偶数时  a^b%c==(a^(b/2)*a^(b/2))%c== (a^(b/2)%c*a^(b/2)%c)%c//当b为基数时 a^b%c==(a^(b/2)*a^(b/2)*a)%c== (a^(b/2)%c*a^(b/2)%c*a%c)%c