51 lines
1.1 KiB
C++
51 lines
1.1 KiB
C++
#include<iostream>
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#include<cstdio>
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#include<cstdlib>
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#include<cstring>
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#include<string>
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#include<queue>
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#include<algorithm>
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#include<map>
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#include<iomanip>
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#define INF 99999999
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using namespace std;
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const int MAX=6000+10;
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int n,size,head[MAX],pre[MAX];
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int temp[2],val[MAX];
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struct Edge{
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int v,next;
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Edge(){}
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Edge(int V,int NEXT):v(V),next(NEXT){}
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}edge[MAX];
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void Init(int num){
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for(int i=0;i<=num;++i)head[i]=-1,pre[i]=0;
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size=0;
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}
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void InsertEdge(int u,int v){
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edge[size]=Edge(v,head[u]);
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head[u]=size++;
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}
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void dfs(int u){
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int dp[2]={0,0};
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for(int i=head[u];i != -1;i=edge[i].next){
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int v=edge[i].v;
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dfs(v);
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dp[0]=dp[0]+max(temp[0],temp[1]);
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dp[1]=dp[1]+temp[0];
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}
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temp[0]=dp[0];
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temp[1]=dp[1]+val[u];
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}
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int main(){
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int u,v;
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while(~scanf("%d",&n)){
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Init(n);
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for(int i=1;i<=n;++i)scanf("%d",&val[i]);
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while(scanf("%d%d",&v,&u),u+v)pre[v]=u;
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for(int i=1;i<=n;++i)InsertEdge(pre[i],i);
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dfs(0);
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printf("%d\n",temp[0]);
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}
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return 0;
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}
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