UVA 10407 差分思想的运用

就是每两项相减，肯定能被模数整除。

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;

const int Maxn=1010;
int f[Maxn],n,Ans;
int Gcd(int a,int b) {if (b==0) return a; return Gcd(b,a%b);}
inline int Abs(int x) {return x>0?x:-x;}
int main()
{
    while (true)
    {
        n=0;
        scanf("%d",&f[++n]);
        if (f[n]==0) break;
        while (f[n]!=0) scanf("%d",&f[++n]);
        n--;
        for (int i=1;i<n;i++)
            f[i]=f[i]-f[i+1];
        Ans=f[1];
        for (int i=2;i<n;i++)
            Ans=Gcd(f[i]==0?Ans:f[i],Ans);
        printf("%d
",Abs(Ans));
    }
    return 0;
}