bzoj3943[Usaco2015 Feb]SuperBull*

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define maxn 2010
 5 #define inc(i,j,k) for(int i=j;i<=k;i++)
 6 using namespace std;
 7 
 8 inline int read(){
 9     char ch=getchar(); int f=1,x=0;
10     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
11     while(ch>=‘0‘&&ch<=‘9‘)x=x*10+ch-‘0‘,ch=getchar();
12     return f*x;
13 }
14 int a[maxn],fa[maxn],n,cnt; long long ans;
15 struct e{int f,t,w;}; e es[maxn*maxn]; int ess;
16 bool cmp(e a,e b){return a.w>b.w;}
17 int find(int x){
18     return x==fa[x]?x:fa[x]=find(fa[x]);
19 }
20 int main(){
21     n=read(); inc(i,1,n)a[i]=read(),fa[i]=i;
22     inc(i,1,n)inc(j,i+1,n)es[++ess]=(e){i,j,a[i]^a[j]};
23     sort(es+1,es+1+ess,cmp);
24     inc(i,1,ess){
25         int x=find(es[i].f),y=find(es[i].t);
26         if(x!=y)fa[x]=y,ans+=es[i].w,cnt++; if(cnt==n-1)break;
27     }
28     printf("%lld",ans); return 0;
29 }