杭电2710

Max Factor

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2450    Accepted Submission(s): 749

Problem Description

To improve the organization of his farm, Farmer John labels each of his N (1 <= N <= 5,000) cows with a distinct serial number in the range 1..20,000. Unfortunately, he is unaware that the cows interpret some serial numbers as better than others. In particular, a cow whose serial number has the highest prime factor enjoys the highest social standing among all the other cows.

(Recall that a prime number is just a number that has no divisors except for 1 and itself. The number 7 is prime while the number 6, being divisible by 2 and 3, is not).

Given a set of N (1 <= N <= 5,000) serial numbers in the range 1..20,000, determine the one that has the largest prime factor.

Input

* Line 1: A single integer, N

* Lines 2..N+1: The serial numbers to be tested, one per line

Output

* Line 1: The integer with the largest prime factor. If there are more than one, output the one that appears earliest in the input file.

Sample Input

436384042

Sample Output

38
 
/*题目的意思是求给出的几个数值中的最大且为素数的除数*/#include <iostream>#include <string.h>#define size 20005using namespace std;int main(){int s[size];int flag;int i,j;int n,t;int max;memset(s,0,sizeof(s));///////用素数筛选法，筛选出所有素数。s[1]=1;for(i=2;i<=size;i++)if(s[i]==0)for(j=i;j<=size;j+=i)s[j]=i;while(cin>>t){max=0;for(i=0;i<t;i++){cin>>n;if(s[n]>max)//////找到最大的那个素数{max=s[n];flag=n;}}cout<<flag<<endl;}return 0;}