[高斯消元 线性基 贪心 拟阵] BZOJ 3105 [cqoi2013]新Nim游戏

#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<functional>
using namespace std;
typedef long long ll;

inline char nc(){
static char buf[100000],*p1=buf,*p2=buf;
if (p1==p2) { p2=(p1=buf)+fread(buf,1,100000,stdin); if (p1==p2) return EOF; }
return *p1++;
}
inline void read(int &x){
char c=nc(),b=1;
for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;
for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;
}

const int N=100005,K=31;

int n,a
;
int base[K+5];
ll ans;

int main()
{
freopen("t.in","r",stdin);
freopen("t.out","w",stdout);
read(n);
for (int i=1;i<=n;i++) read(a[i]),ans+=a[i];
sort(a+1,a+n+1,greater<int>());
for (int i=1;i<=n;i++)
{
int tem=a[i];
for (int p=K;~p;p--)
if (a[i]>>p&1)
{
if (!base[p]){
base[p]=i; break;
}
else
a[i]^=a[base[p]];
}
if (a[i]) ans-=tem;
}
printf("%lld\n",ans);
return 0;
}