计算x的n次幂及运行时间

编写程序实现计算x的n次幂

采用两种算法

朴素算法:x*x*x......

分治算法:

  n为偶数:x的n/2次幂*x的n/2次幂

  n为奇数:x的(n-1)/2次幂*x的(n-1)/2次幂

代码

#include<bits/stdc++.h>
using namespace std;
//朴素算法
int pusu(int x,int n)
{
    int num=1;
    for(int i=0;i<n;i++)
    {
        num*=x;
    }
    return num;
}
//分治算法----快速幂
int fenzhi(int x,int n)
{
    int num=1;
    while(n)
    {
        if(n%2==1)
        {
            num*=x;
            n--;
        }
        x*=x;
        n/=2;
    }
    return num;
}
int main()
{
    int x,n;
    cin>>x>>n;
    int result;
    clock_t start_time=clock();
    {
         result=pusu(x,n);
    }
    clock_t end_time=clock();
    cout<<"朴素算法结果:"<<result<<endl;
    printf("Running time is: %lfms\n",static_cast<double>(end_time-start_time)/CLOCKS_PER_SEC*1000);
    clock_t start_time1=clock();
    {
         result=fenzhi(x,n);
    }
    clock_t end_time1=clock();
    cout<<"分治算法结果:"<<result<<endl;
    printf("Running time is: %lfms\n",static_cast<double>(end_time1-start_time1)/CLOCKS_PER_SEC*1000);

    return 0;
}

测试数据