Submission #491644

#	Time	Username	Problem	Language	Result	Execution time	Memory
491644		Sho10	Arboras (RMI20_arboras)	C++17	24 / 100	5039 ms	24708 KiB

arboras

#include <bits/stdc++.h> //Andrei Alexandru a.k.a Sho
#define ll long long
#define double long double
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define aint(a) (a).begin(), (a).end()
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define pi pair
#define rc(s) return cout<<s,0
#define endl '\n'
#define mod 1000000007
#define PI 3.14159265359
#define INF 1000000005
#define LINF 1000000000000000005ll
#define CODE_START  ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
ll n,q,par[100005],mx[100005],ans=0,dp[100005][5],nw=0,res[100005][5];
map<pair<ll,ll>,ll>d;
vector<ll>g[100005];
void dfs(ll node,ll par){
    multiset<pair<ll,ll>>s;
for(auto it : g[node]){
    if(it!=par){
        dfs(it,node);
        s.insert(mp(dp[it][1]+d[mp(node,it)],it));
    }
}
auto it=s.end();
if(s.size()>=1){it--;
pair<ll,ll>p=*(it);
dp[node][1]=p.f;
res[node][1]=p.s;
}
if(s.size()>=1)
s.erase(s.find(*(it)));
if(s.size()>=1){
        auto it=s.end();
it--;
pair<ll,ll>p=*(it);
dp[node][2]=p.f;
res[node][2]=p.s;
}
ans+=dp[node][1]+dp[node][2];
ans%=mod;
}
void update(ll node){
if(node==-1){
    return;
}
ll mx=0;
ans-=dp[node][1];
ans-=dp[node][2];
//cout<<dp[node][1]<<' '<<dp[node][2]<<' '<<node<<endl;
while(ans<0){
    ans+=mod;
}
mx=dp[nw][1]+d[mp(node,nw)];
//cout<<mx<<' '<<nw<<' '<<res[node][1]<<' '<<res[node][2]<<endl;
if(mx>dp[node][1]&&nw!=res[node][2]){
if(nw!=res[node][1]){
    dp[node][2]=dp[node][1];
    res[node][2]=res[node][1];
}
       dp[node][1]=mx;
    res[node][1]=nw;
}else if(mx>dp[node][2]&&nw!=res[node][1]){
dp[node][2]=mx;
res[node][2]=nw;
}
if(dp[node][2]>dp[node][1]){
    swap(dp[node][2],dp[node][1]);
    swap(res[node][2],res[node][1]);
}
//cout<<dp[node][1]<<' '<<dp[node][2]<<' '<<node<<endl;
ans+=dp[node][1];
ans+=dp[node][2];
ans%=mod;
nw=node;
update(par[node]);
}
int32_t main(){
CODE_START;
cin>>n;
for(ll i=1;i<n;i++)
{
    ll x;
    cin>>x;
    par[i]=x;
    g[x].pb(i);
}
for(ll i=0;i<=n;i++)
{
    res[i][1]=-1;
    res[i][2]=-1;
}
for(ll i=1;i<n;i++)
{
    ll dist;
    cin>>dist;
    d[mp(par[i],i)]=dist;
}
par[0]=-1;
dfs(0,-1);
cout<<ans<<endl;
cin>>q;
while(q--){
ll x,y;
cin>>x>>y;
d[mp(par[x],x)]+=y;
nw=x;
update(par[x]);
cout<<ans<<endl;
}
}
/*
5
0 0 1 1
0 0 0 0
5
1 2
2 2
3 2
4 2
4 1
*/

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 0 / 31
• Subtask 4: 0 / 45