POJ-1830

/**
          题意：给一些开关，开某一个开关之后有的开关也会变化
          做法：高斯消元  线性代数
**/
#include <iostream>
#include <string.h>
#include <stdio.h>
#include <algorithm>
#include <cmath>
#define maxn 50
using namespace std;
int mmap[maxn][maxn];
int start[maxn];
int eed[maxn];
int guess(int equ,int val)
{
    int k=0,col = 0;
    int max_r = 0;
    for(k=0; k<equ&&col<val; k++,col++)
    {
        max_r = k;
        for(int i=k+1; i<equ; i++)
        {
            if(abs(mmap[i][col]) > abs(mmap[max_r][col]))
            {
                max_r = i;
            }
        }
        if(max_r != k)
        {
            for(int i=k; i<val+1; i++)
            {
                swap(mmap[k][i],mmap[max_r][i]);
            }
        }
        if(mmap[k][col] == 0)
        {
            k--;
            continue;
        }
        for(int i=k+1; i<equ; i++)
        {
            if(mmap[i][col] != 0)
            {
                for(int j=col; j<val+1; j++)
                {
                    mmap[i][j] ^= mmap[k][j];
                }
            }
        }
    }
    ///上三角
    for(int i=k; i<equ; i++)
    {
        if(mmap[i][col]!=0) return -1;
    }
    return val-k;
}
int main()
{
//#ifndef ONLINE_JUDGE
//    freopen("in.txt","r",stdin);
//#endif // ONLINE_JUDGE
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int n;
        scanf("%d",&n);
        memset(start,0,sizeof(start));
        memset(eed,0,sizeof(eed));
        for(int i=0; i<n; i++)
        {
            scanf("%d",&start[i]);
        }
        for(int i=0; i<n; i++)
        {
            scanf("%d",&eed[i]);
        }
        int u,v;
        memset(mmap,0,sizeof(mmap));
        while(scanf("%d %d",&u,&v))
        {
            if(u == 0 && v == 0) break;
            u--;
            v--;
            mmap[v][u] = 1;
        }
        for(int i=0; i<n; i++)
        {
            mmap[i][i] = 1;
        }
        for(int i=0; i<n; i++)
        {
            mmap[i][n] = start[i]^eed[i];
        }
        int res = guess(n,n);
        if(res == -1) printf("Oh,it‘s impossible~!!\n");
        else printf("%d\n",1<<res);
    }
    return 0;
}