HDU3949：XOR 高斯消元求线性基+二进制拆分

#include<iostream>
#include<cstdio>
#include<cstring>
#define ll long long
using namespace std;
int now,zero;
ll a[10005];
int T,n,m;
inline ll read()
{
ll a=0,f=1; char c=getchar();
while (c<'0'||c>'9') {if (c=='-') f=-1; c=getchar();}
while (c>='0'&&c<='9') {a=a*10+c-'0'; c=getchar();}
return a*f;
}
inline void Gauss()
{
int y; now=1; zero=0;
for (int k=60;~k;k--)
{
for (y=now;y<=n;y++)
if ((1ll<<k)&a[y]) break;
if (y>n) continue;
if (now!=y) swap(a[now],a[y]);
for (int i=1;i<=n;i++)
if (i!=now&&((1ll<<k)&a[i])) a[i]^=a[now];
now++;
}
now--;
if (now!=n) zero=1;
}
ll query(ll x)
{
ll ans=0;
x-=zero;
if (!x) return 0;
if (x>=(1ll<<now)) return -1;
for (int i=1;i<=now;i++)
if (x&(1ll<<(now-i))) ans^=a[i];
return ans;
}
int main()
{
T=read();
for (int t=1;t<=T;t++)
{
n=read();
for (int i=1;i<=n;i++) a[i]=read();
Gauss();
m=read();
printf("Case #%d:\n",t);
while (m--)
{
int x=read();
printf("%lld\n",query(x));
}
}
return 0;
}