Submission #985752

#	Time	Username	Problem	Language	Result	Execution time	Memory
985752		alexdd	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	379 ms	45628 KiB

diameter

#include<bits/stdc++.h>
using namespace std;
#define int long long

struct node
{
    int a,b,ab,bc,abc;
};
node combine(node x, node y)
{
    node aux;
    aux.a = max(x.a,y.a);
    aux.b = max(x.b,y.b);
    aux.ab = max(max(x.ab,y.ab),x.a+y.b);
    aux.bc = max(max(x.bc,y.bc),x.b+y.a);
    aux.abc = max({max(x.abc,y.abc),x.a+y.bc,x.ab+y.a});
    return aux;
}
node aint[530000];
int lazy[530000];

void baga(node &x, int newv)
{
    x.a += newv;
    x.b -= 2*newv;
    x.ab -= newv;
    x.bc -= newv;
}
void propagate(int nod)
{
    baga(aint[nod*2],lazy[nod]);lazy[nod*2]+=lazy[nod];
    baga(aint[nod*2+1],lazy[nod]);lazy[nod*2+1]+=lazy[nod];
    lazy[nod]=0;
}
void upd(int nod, int st, int dr, int le, int ri, int newv)
{
    if(le>ri)
        return;
    if(le==st && dr==ri)
    {
        baga(aint[nod],newv);lazy[nod]+=newv;
        return;
    }
    propagate(nod);
    int mij=(st+dr)/2;
    upd(nod*2,st,mij,le,min(mij,ri),newv);
    upd(nod*2+1,mij+1,dr,max(mij+1,le),ri,newv);
    aint[nod] = combine(aint[nod*2],aint[nod*2+1]);
}

int n,q,maxw;
vector<int> con[100005];
int tin[100005],tout[100005],timer;
int parent[100005];
pair<pair<int,int>,int> e[100005];
void dfs(int nod)
{
    tin[nod]=++timer;
    for(auto adj:con[nod])
    {
        if(e[adj].first.first==parent[nod])
            continue;
        if(e[adj].first.second==nod)
            swap(e[adj].first.first,e[adj].first.second);
        parent[e[adj].first.second]=nod;
        dfs(e[adj].first.second);
        timer++;
    }
    tout[nod]=timer;
}

signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin>>n>>q>>maxw;
    for(int i=0;i<n-1;i++)
    {
        cin>>e[i].first.first>>e[i].first.second>>e[i].second;
        con[e[i].first.first].push_back(i);
        con[e[i].first.second].push_back(i);
    }
    dfs(1);
    for(int i=0;i<n-1;i++)
    {
        upd(1,1,timer,tin[e[i].first.second],tout[e[i].first.second],e[i].second);
    }
    int u,d,ult=0;
    while(q--)
    {
        cin>>u>>d;
        u = (u+ult)%(n-1);
        d = (d+ult)%maxw;
        upd(1,1,timer,tin[e[u].first.second],tout[e[u].first.second],d-e[u].second);
        e[u].second = d;
        ult = aint[1].abc;
        cout<<ult<<"\n";
    }
    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 7 / 7
• Subtask 4: 18 / 18
• Subtask 5: 24 / 24
• Subtask 6: 27 / 27