AtCoder Grand Contest 018

A - Getting Difference

Time limit : 2sec / Memory limit : 256MB

Score : 300 points

Problem Statement There is a box containing N balls. The i-th ball has
the integer Ai written on it. Snuke can perform the following
operation any number of times:

Take out two balls from the box. Then, return them to the box along
with a new ball, on which the absolute difference of the integers
written on the two balls is written. Determine whether it is possible
for Snuke to reach the state where the box contains a ball on which
the integer K is written.

Constraints 1≤N≤105 1≤Ai≤109 1≤K≤109
All input values are integers.
Input Input is given from Standard Input in the following format:

N K
A1 A2 … AN

Output If it is possible for Snuke to reach the state where the box
contains a ball on which the integer K is written, print POSSIBLE; if
it is not possible, print IMPOSSIBLE.

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原地址戳

题解

就是一个更相减损术，hxm大佬%%%%%
找这些数的最大公约数
k%公约数为零就行

#include<algorithm>
#include<cstring>
#include<cstdio>
#include<iostream>
using namespace std;
int n,k,ans,x;
bool pan;
int pan2;
int main()
{
    scanf("%d%d",&n,&k);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&x);
        ans=__gcd(x,ans);
        if(k%ans==0)pan=1;
        pan2=max(pan2,x);
    }
    if(pan==1&&pan2>=k)
    cout<<"POSSIBLE"<<endl;
    else cout<<"IMPOSSIBLE"<<endl;
    return 0;
}