59 lines
1.2 KiB
C++
59 lines
1.2 KiB
C++
#include<cstdio>
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#include<cstring>
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#include<algorithm>
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using namespace std;
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const int maxn=100005;
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const int maxmem=maxn*31;
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int n,d[maxn],E[maxmem][2],cnt;
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struct Edge { int v,w; Edge *nxt; };
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Edge mem[maxn*2],*G[maxn],*ecnt;
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inline void AddEdge(int u,int v,int w) { ecnt->v=v; ecnt->w=w; ecnt->nxt=G[u]; G[u]=ecnt++; }
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void dfs(int u,int fa,int val)
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{
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d[u]=val;
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for(Edge *it=G[u];it;it=it->nxt) if(it->v!=fa) dfs(it->v,u,val^it->w);
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}
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inline void insert(int x)
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{
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int p=0;
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for(int i=30;i>=0;i--)
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{
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int now=(x>>i)&1;
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if(!E[p][now]) E[p][now]=++cnt;
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p=E[p][now];
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}
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}
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inline int query(int x)
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{
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int p=0,res=0,w=0;
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for(int i=30;i>=0;i--)
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{
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int now=(x>>i)&1;
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if(E[p][now^1]) { p=E[p][now^1]; res+=1<<i; }
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else p=E[p][now];
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}
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return res;
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}
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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while(scanf("%d",&n)==1)
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{
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ecnt=mem; memset(G,0,sizeof(G));
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memset(E,0,sizeof(E)); cnt=0;
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for(int i=0;i<n-1;i++)
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{
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int u,v,w; scanf("%d%d%d",&u,&v,&w); u++; v++;
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AddEdge(u,v,w); AddEdge(v,u,w);
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}
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dfs(1,-1,0);
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int res=0;
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for(int i=1;i<=n;i++) insert(d[i]);
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for(int i=1;i<=n;i++) res=max(res,query(d[i]));
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printf("%d\n",res);
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}
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return 0;
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}
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