D. Captain Flint and Treasure（拓扑排序+贪心）

题目链接

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn=2e5+5;
int n,in[maxn],b[maxn];
ll ans,a[maxn];
vector<int>g[maxn],v;
queue<int>q;
stack<int>s;
int main()
{
	scanf("%d",&n);
	for(int i=1;i<=n;++i) scanf("%lld",&a[i]);
	for(int i=1;i<=n;++i)
	{
		scanf("%d",&b[i]);
		if(b[i]!=-1)
		{
			g[i].push_back(b[i]);
			in[b[i]]++;
		}
	}
	ll ans=0;
	for(int i=1;i<=n;++i) if(in[i]==0) q.push(i);
	while(!q.empty())
	{
		int top=q.front();
		q.pop();
		if(a[top]>=0) ans+=a[top],v.push_back(top);
		else s.push(top);
		for(int to:g[top])
		{
			if(a[top]>=0) a[to]+=a[top];
			--in[to];
			if(!in[to]) q.push(to);
		}
	}
	while(!s.empty())
	{
		int top=s.top();
		s.pop();
		ans+=a[top];
		v.push_back(top);
	}
	printf("%lld\n",ans);
	for(auto i:v) printf("%d ",i);	
}