poj 1830 开关问题 1830 高斯消元

#include<cstdio>
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
using namespace std;
int a[35][35];
int s[35];
int gaoS(int n)
{
int i=0,j;
for(i=0,j=0;i<n&&j<n;j++)
{
int k=i;
for(;k<n;k++)
if(a[k][j])break;
if(a[k][j])
{
for(int r=0;r<=n;r++) swap(a[i][r],a[k][r]);

for(int k=0;k<n;k++)
if(k!=i&&a[k][j])
for(int r=0;r<=n;r++)
a[k][r]^=a[i][r];
i++;
}
}
for(int j=i;j<n;j++)
if(a[j]
)return -1;
return 1<<(n-i);
}
int main()
{
int t;
scanf("%d",&t);
while(t--)
{
int n;
memset(a,0,sizeof(a));
scanf("%d",&n);
for(int i=0;i<n;i++)scanf("%d",&s[i]);
for(int i=0;i<n;i++)
{
int pre = s[i];
scanf("%d",&s[i]);
a[i]
= s[i]^pre;
a[i][i] = 1;
}
int c,d;
while(scanf("%d%d",&c,&d))
{
if(c==0&&d==0)break;
a[d-1][c-1] = 1;
}
int ans = gaoS(n);
if(ans == -1)printf("Oh,it's impossible~!!\n");
else printf("%d\n",ans);
}
return 0;
}