Given any positive integer N, you are supposed to find all of its prime factors, and write them in the format N = p1k1×p2k2×⋯×pmkm.
Input Specification:
Each input file contains one test case which gives a positive integer N in the range of long int.
Output Specification:
Factor N in the format N =
p1^
k1*
p2^
k2*
…*
pm^
km, where pi's are prime factors of N in increasing order, and the exponent ki is the number of pi -- hence when there is only one pi, ki is 1 and must NOT be printed out.
Sample Input:
97532468
Sample Output:
97532468=2^2*11*17*101*1291
题目大意:将一个数分解为若干素数之积;
解题思路:建立素数表
#include<vector>
#include<iostream>
using namespace std;
std::vector<int> prime(500000,1);
int main()
{ int i,j=2;
for(i=2;i*j<500000;i++)
for(j=2;i*j<500000;j++)
prime[i*j]=0;
long int a;
scanf("%ld",&a);
printf("%ld=",a);
if(a==1)
cout<<1;
int k=2,flag=0;
while(a!=1){
int cnt=0;
while(prime[k]!=0&&a%k==0){
cnt++;
a=a/k;
}
if(cnt!=0){
if(flag==1)
printf("*");
printf("%d",k);
flag=1;
}
if(cnt>1)
printf("^%d",cnt);
k++;
}
system("pause");
}