HDU 2136 打表

Largest prime factor

Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1624    Accepted Submission(s): 499

Problem Description

Everybody knows any number can be combined by the prime number.
Now, your task is telling me what position of the largest prime factor.
The position of prime 2 is 1, prime 3 is 2, and prime 5 is 3, etc.
Specially, LPF(1) = 0.

 

 

Input

Each line will contain one integer n(0 < n < 1000000).

 

 

Output

Output the LPF(n).

 

 

Sample Input

1 2 3 4 5

 

 

Sample Output

0 1 2 1 3

//求一個數的最大素因子是第幾個素數,打表 #include<stdio.h> #include<string.h> int a[1000000]; int main() { int i,j,k; for(i=0;i<1000000;i++) a[i]=0; for(i=2,k=0;i<1000000;i++) { if(!a[i]) { k++; for(j=i;j<1000000;j+=i) a[j]=k; } } int n; while(scanf("%d",&n)!=EOF) { printf("%d/n",a[n]); } return 0; }