UVA - 1594 Ducci Sequence [vector+simulation]

#include<iostream>
#include<string>
#include<vector>
#include<cmath>
using namespace std;
vector<int> v;
int len;
void Transform()
{
    int a = v[0];
    for (int i = 0; i < len - 1; i++) v[i] = abs(v[i] - v[i + 1]);
    v [len - 1] = abs (v [len - 1] - a);
}
bool Judge()
{
    for (int i = 0; i < len; i++)
    {
        if(v[i]) return false;
    }
    return true;
}
intmain()
{
    int n;
    while(cin >> n && n)
    {
        while(n--)
        {

        cin >> len;
        v.clear();
        for (int i = 0; i < len; i++)
        {
            int x; cin >> x;
            v.push_back(x);
        }
        int t = 1000;
        while(t--) Transform();
         if(Judge())
            cout << "ZERO" << endl;
         else cout <<"LOOP" << endl;
        }


    }
}