【BZOJ2460】元素（拟阵）

题意：给定n个物品，每个物品有属性x和价值y，要求从中选出一些使得价值和最大并且其中没有属性xor和为0的非空子集

n<=1000，x<=1e18，y<=1e4

思路：没有xor和为0的非空子集本来就是线性基的定义

拟阵，直接按价值排序之后贪心插入并维护线性基

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> PII;
typedef pair<ll,ll> Pll;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef pair<ll,ll>P;
#define N  100010
#define M  1000000
#define INF 1e9
#define fi first
#define se second
#define MP make_pair
#define pb push_back
#define pi acos(-1)
#define mem(a,b) memset(a,b,sizeof(a))
#define rep(i,a,b) for(int i=(int)a;i<=(int)b;i++)
#define per(i,a,b) for(int i=(int)a;i>=(int)b;i--)
#define lowbit(x) x&(-x)
#define Rand (rand()*(1<<16)+rand())
#define id(x) ((x)<=B?(x):m-n/(x)+1)
#define ls p<<1
#define rs p<<1|1
#define fors(i) for(auto i:e[x]) if(i!=p)

const int MOD=1e9+7,inv2=(MOD+1)/2;
      double eps=1e-6;
      int dx[4]={-1,1,0,0};
      int dy[4]={0,0,-1,1};

int read()
{
   int v=0,f=1;
   char c=getchar();
   while(c<48||57<c) {if(c=='-') f=-1; c=getchar();}
   while(48<=c&&c<=57) v=(v<<3)+v+v+c-48,c=getchar();
   return v*f;
}

ll readll()
{
   ll v=0,f=1;
   char c=getchar();
   while(c<48||57<c) {if(c=='-') f=-1; c=getchar();}
   while(48<=c&&c<=57) v=(v<<3)+v+v+c-48,c=getchar();
   return v*f;
}

struct node
{
    ll x;
    int y;
}a[N];

bool cmp(node a,node b)
{
    return a.y>b.y;
}

struct base
{
    ll d[65],p[65];
    int cnt;

    base()
    {
        mem(d,0);
        mem(p,0);
        cnt=0;
    }

    bool insert(ll x)
    {
        //if(x==0) return 0;
        per(i,62,0)
         if(x>>i&1)
         {
             if(!d[i])
             {
                 d[i]=x;
                 break;
             }
             x^=d[i];
         }
        return x>0;
    }
}T;

int main()
{
    int n=read();
    rep(i,1,n) scanf("%lld%d",&a[i].x,&a[i].y);
    sort(a+1,a+n+1,cmp);
    base T;
    int ans=0;
    rep(i,1,n) if(T.insert(a[i].x)) ans+=a[i].y;
    printf("%d
",ans);
    return 0;
}