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| #include <bits/stdc++.h>
using namespace std;
const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;
#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))
#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
using ll=long long;
ll n,a[(int)1e4+9],dp[(int)1e4+9][2];
vi g[(int)1e4+9];
bitset<(int)1e4+9> ez;
void dfs(int u){
dp[u][0]=0,dp[u][1]=a[u];
for(auto it:g[u]){
dfs(it);
dp[u][0]+=max(dp[it][1],dp[it][0]),dp[u][1]+=dp[it][0];
}
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cin>>n;
f(i,1,n)cin>>a[i];
for(int i=2,x,y;i<=n;++i){
cin>>x>>y;
g[y].push_back(x);
ez[x]=1;
}
f(i,1,n){
if(!ez[i]){
dfs(i);
cout<<max(dp[i][0],dp[i][1]);
return 0;
}
}
return 0;
}
|