HDOJ 1019 Least Common Multiple(最小公倍数问题)

Problem Description

The least common multiple (LCM) of a set of positive integers is the smallest positive integer which is divisible by all the numbers in the set. For example, the LCM of 5, 7 and 15 is 105.

Input

Input will consist of multiple problem instances. The first line of the input will contain a single integer indicating the number of problem instances. Each instance will consist of a single line of the form m n1 n2 n3 … nm where m is the number of integers in the set and n1 … nm are the integers. All integers will be positive and lie within the range of a 32-bit integer.

Output

For each problem instance, output a single line containing the corresponding LCM. All results will lie in the range of a 32-bit integer.

Sample Input

2

3 5 7 15

6 4 10296 936 1287 792 1

Sample Output

105

10296

import java.util.Scanner;

public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int t = sc.nextInt();
while(t-->0){
int n = sc.nextInt();
int a[] = new int
;
for(int i=0;i<n;i++){
a[i] = sc.nextInt();
}
int k = a[0];
for(int i=1;i<n;i++){
int b = a[i];
if(k>b){
b=b^k;
k=b^k;
b=b^k;
}
k=su(b,k,mod(b,k));
}

System.out.println(k);

}
}

//最小公倍数。
private static int su(int b, int k, int mod) {
return k*(b/mod);
}

//求最大公约数，辗转相除法。b>k
private static int mod(int b, int k) {
while(k>0){
int m = b%k;
b=k;
k=m;
}
return b;
}
}