蒙哥马利快速幂摸算法

快速求幂取摸

a^b mod m! 0<a,b<1000000000. 思路：用for循环循环b次，求得答案后再取摸，肯定超时！

上代码：

#include<iostream>#include<string>#include <cstdio>#include <cmath>#include<vector>#include<algorithm>#include<sstream>#include<cstdlib>using namespace std;int main(){__int64 a,b,m;int n;cin>>n;while(n--){cin>>a>>b>>m;a%=m;__int64 tmp=1;while(b){if(b%2==0){a=(a*a)%m;b/=2;}else {tmp=tmp*a%m;b-=1;}}cout<<tmp<<endl;}return 0;}

sample inpout:

3

2 1 10000 

2 10 10000

3 10 10000

sample output:

2

1024

9049