2460: [BeiJing2011]元素

2460: [BeiJing2011]元素

链接

分析：

　　贪心的想：首先按权值排序，然后从大到小依次放，能放则放。然后用线性基维护是否合法。

代码：

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#include<cmath>
#include<cctype>
#include<set>
#include<queue>
#include<vector>
#include<map>
#define pa pair<int,LL>
using namespace std;
typedef long long LL;

inline LL read() {
    LL x=,f=;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-;
    for(;isdigit(ch);ch=getchar())x=x*+ch-'';return x*f;
}

const int N = ;
pa A[N];
LL b[N];

bool Insert(LL x) {
    for (int i = ; ~i; --i)
        if ((x >> i) & ) {
            if (b[i]) x ^= b[i];
            else {
                b[i] = x;
                return ;
            }
        }
    return ;
}

int main() {
    int n = read();
    for (int i = ; i <= n; ++i)
        A[i].second = read(), A[i].first = read();
    sort(A + , A + n + );
    LL Ans = ;
    for (int i = n; i >= ; --i)
        if (Insert(A[i].second)) Ans += A[i].first;
    cout << Ans;
    return ;
}