题面
题解
一个方案合法,当且仅当选取的01串凑不出0.
因此就是要使得选取的01串全在线性基内,具体原因可以看这道题:[CQOI2013]新Nim游戏 线性基
要使得魔力值最大,只需要按法力值从大到小,贪心的往线性基中加串就可以了
#include<bits/stdc++.h>
using namespace std;
#define R register int
#define AC 1100
#define LL long long
int n; LL ans;
LL f[AC];
struct node{LL x, w;}s[AC];
inline bool cmp(node a, node b){return a.w > b.w;}
inline LL read()
{
LL x = 0;char c = getchar();
while(c > '9' || c < '0') c = getchar();
while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
return x;
}
void pre()
{
n = read();
for(R i = 1; i <= n; i ++) s[i].x = read(), s[i].w = read();
sort(s + 1, s + n + 1, cmp);
}
void work()
{
for(R i = 1; i <= n; i ++)//从高开始贪心
{
LL x = s[i].x, maxn = 1LL << 60; bool done = false;
for(R j = 60; ~j; j --, maxn >>= 1)
{
if(!(x & maxn)) continue;
if(!f[j]) {f[j] = x, done = true; break;}
else x ^= f[j];
}
if(done) ans += s[i].w;//加入线性基就要拿走
}
printf("%lld\n", ans);
}
int main()
{
// freopen("in.in", "r", stdin);
pre();
work();
// fclose(stdin);
return 0;
}
原文地址:https://www.cnblogs.com/ww3113306/p/10354336.html
时间: 2024-10-10 15:36:25