[暑假集训--数论]hdu1019 Least Common Multiple

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.

InputInput 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.
OutputFor 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

a*b=gcd(a,b)*lcm(a,b)

lcm(a,b)=a*b/gcd(a,b)

求n个数的lcm，每加一个数进去就ans=ans/__gcd(ans,x)*x

除法放中间是为了防爆int

 #include<cstdio>

 #include<algorithm>

 #define LL long long

 using namespace std;

 inline LL read()

 {

     LL x=,f=;char ch=getchar();

     while(ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}

     while(ch>=''&&ch<=''){x=x*+ch-'';ch=getchar();}

     return x*f;

 }

 int T;

 int main()

 {

     T=read();

     for (int i=;i<=T;i++)

     {

         int x=read(),now=read(),y;

         for (int i=;i<=x;i++)

         {

             y=read();

             now=now/__gcd(now,y)*y;

         }

         printf("%d\n",now);

     }

 }

hdu 1019

巴特西

[暑假集训--数论]hdu1019 Least Common Multiple

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