1466: [蓝桥杯2019初赛]等差数列

#include <iostream>
#include <algorithm>

using namespace std;
const int maxn = 100010;
int n,a[maxn];

int gcd(int a,int b){
    return b ? gcd(b, a % b) : a;
}

int main(){
    cin>>n;
    for(int i = 1;i <= n; i++)
        cin>>a[i];
    sort(a + 1, a + 1 + n);
    for(int i = 2; i <= n; i++)
        a[i] -= a[1];
    int d = a[2];
    for(int i = 3; i <= n; i++)
        d = gcd(d, a[i]);
    if(d)
        cout<<a[n] / d + 1<<endl;
    else
        cout<<n<<endl;
    return 0;
}