luoguP4570 [BJWC2011] element (linear-yl)

Transmission: https://www.luogu.org/problem/P4570

Meaning of the questions: Given a number of items, each item has two properties, the magic number and value now selected a few of these items, select the required number of items it can not be the exclusive or the magic of 0 and maximum value add up, find out of this maximum.

analysis:

Given the nature of a linear group: the same number of linear groups is the same set of elements.

So greedy consider the answer. If the current item number to be inserted, then the answer is contributing.

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 const int maxn=1010;
 5 struct node{
 6     ll x,y;
 7 }a[maxn]; 
 8 bool cmp(node p,node q){return p.y>q.y;}
 9 struct Linear_basis{
10     ll b[65],tot;
11     bool insert(ll x){
12         for (int i=60; I> = 0 ; i-- ) {
 13 is              IF (X & (1LL << I)) {
 14                  IF (! B [I]) {
 15                      B [I] = X; BREAK ;
 16                  } 
 . 17                  X ^ = B [I];
 18 is              }
 . 19          }
 20 is          return X> 0 ;   // if insertable true: insertable, false: not insert 
21 is      }
 22 is  } an LB;
 23 is  int main () {
 24      int n-; Scanf ( " % D " , &n); ll x;
25     for (int i=1;i<=n;i++) scanf("%lld%lld",&a[i].x,&a[i].y);
26     sort(a+1,a+1+n,cmp);
27     ll ans=0;
28     for (int i=1;i<=n;i++){
29         bool f=LB.insert(a[i].x);
30         if (f) ans+=a[i].y;
31     }
32     printf("%lld\n",ans);
33      Return  0 ; 
34 }