Submission #93572

#	Time	Username	Problem	Language	Result	Execution time	Memory
93572		FedericoS	Islands (IOI08_islands)	C++14	54 / 100	1100 ms	132096 KiB

islands

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> pll;
/*
#include <fstream>
ifstream in("input.txt");
ofstream out("output.txt");
#define cin in
#define cout out
*/
ll N;
ll x,y;
vector<pll> grafo[1000005];
ll F[1000005];
ll H[1000005];
ll W[1000005];
bool V[1000005];
bool C[1000005];
ll res,ans;
ll s,c,l,r;
priority_queue<pll> PQ;

ll VAL(int k){

	V[k]=true;
	ll a=0;

	for(pll f:grafo[k])
		if(!V[f.first] and !C[f.first])
			a=max(a,f.second+VAL(f.first));

	return a;
}

void DFS(int k, int g){

	if(k==x)
		if(c++>1)
			return;

	ll p=H[k];
	while(PQ.top().second+l<=r)
		PQ.pop();
	ll d=PQ.top().first;
	res=max(res,s+p+d);
	PQ.push({p-s,r});
	r++;

	for(pll f:grafo[k])
		if(C[f.first] and f.first!=g){
			s+=f.second;
			//cout<<"DFS "<<k<<" "<<s<<" "<<p<<" "<<d<<" "<<c<<endl;
			DFS(f.first,k);
			return;
		}

}

int main(){
	cin>>N;
	for(int i=0;i<N;i++){
		cin>>x>>y;
		x--;
		F[i]=x;
		W[i]=y;
		grafo[i].push_back({x,y});
		grafo[x].push_back({i,y});
	}

	for(int i=0;i<N;i++)
		if(!V[i]){

			x=y=i;
			l=0;

			do{
				x=F[x];
				y=F[F[y]];
			}while(x!=y);

			do{
				l++;
				C[x]=true;
				x=F[x];
			}while(x!=y);

			do{
				H[x]=VAL(x);
				x=F[x];
			}while(x!=y);

			r=0;
			s=0;
			c=0;
			res=0;

			while(!PQ.empty())
				PQ.pop();
			PQ.push({-1e18,1e18});

			if(l==2)
				res=max(W[x],W[F[x]])+H[x]+H[F[x]];
			else
				DFS(x,-1);

			ans+=res;
		}

	cout<<ans;

}

• Subtask 1: 27 / 33
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 0 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10