P2043 质因子分解

#include<cstdio> 
#include<cmath>
#include<algorithm>
#include<cstring> 
#include<iostream>
using namespace std;
int ans[10001]={0};

int main(){
    memset(ans,0,sizeof(ans));
    int n;
    cin>>n;
    for(int i=2;i<=n;i++)    
    {  int b=i;
        for(int j=2;j<=n;j++)
        {    while(b%j==0)
            {  ans[j]++;
//                cout<<j<<endl;
                b/=j;
            }
        }
    }
    for(int i=2;i<10001;i++)
    if(ans[i])
    cout<<i<<" "<<ans[i]<<endl;
    return 0;
}
//10!=10*9*8*7*6*5*4*3*2*1
//10!=2*5*3*3*7*2*3*5*2*2*3*2
//10!=(2^8)*(3^4)*(5^2)*7