Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4026 Accepted Submission(s): 1415
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
Author Wiskey
Source HDU 2007-11 Programming Contest_WarmUp
Recommend 威士忌 分析：用筛选法(分解素数技巧),求N的最大素数因子在素数表的位置 #include<iostream> using namespace std; int a[1000000]; int main() { int k=1;//k初始化为1,位置 memset(a,0,sizeof(a)); /*筛选位置*/ for(int i=2;i<1000000;i++)//要到N,而不是sqrt(N) { if(!a[i]) { a[i]=k;//素数i的位置 for(int j=i+i;j<1000000;j+=i) a[j]=k; //构造出j的暂时最大素数因子的位置 k++; } } int n; while(~scanf("%d",&n)) { printf("%d\n",a[n]); } return 0; }
转载于:https://www.cnblogs.com/Su-Blog/archive/2012/08/24/2654759.html
