Submission #1095997

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095997		yoav_s	Dynamic Diameter (CEOI19_diameter)	C++17	0 / 100	5060 ms	26992 KiB

diameter

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<vv> vvv;
typedef pair<ll, ll> p;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef pair<ll, p> tri;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;

#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()

const ll INF = 1e18;
const ll mod = 1e9 + 7;

void findFurtherest(vvp &graph, v &weights, vp &res, ll i)
{
    res[i] = p(0, i);
    for (auto x : graph[i])
    {
        if (res[x.f].f == -1)
        {
            findFurtherest(graph, weights, res, x.f);
            res[i] = max(res[i], p(res[x.f].f + weights[x.s], res[x.f].s));
        }
    }
}

void getRes(vvp &graph, v &weights, vp &furtherest, ll i, vb &visited, v &res)
{
    if (visited[i]) return;
    visited[i] = true;
    ll curMaxi = furtherest[i].f;
    v children;
    for (auto x : graph[i])
    {
        if (!visited[x.f])
        {
            children.pb(furtherest[x.f].f + weights[x.s]);
            getRes(graph, weights, furtherest, x.f, visited, res);
        }
    }
    sort(all(children),greater<ll>());
    if (children.size() >= 2) curMaxi = max(curMaxi, children[0] + children[1]);
    res[i] = curMaxi;
}

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    ll n, q, w;
    cin >> n >> q >> w;
    vtri edges(n - 1);
    for (ll i = 0; i < n - 1; i++)
    {
        cin >> edges[i].s.f >> edges[i].s.s >> edges[i].f;
        edges[i].s.f--; edges[i].s.s--;
    }
    v weight(n - 1);
    for (ll i = 0; i < n - 1; i++) weight[i] = edges[i].f;
    vvp graph(n);
    for (ll i = 0; i < n - 1; i++)
    {
        graph[edges[i].s.f].eb(edges[i].s.s, i);
        graph[edges[i].s.s].eb(edges[i].s.f, i);
    }
    v parent(n, -1);
    stack<p> dfs;
    dfs.emplace(0, 0);
    while (!dfs.empty())
    {
        auto top = dfs.top();
        dfs.pop();
        if (parent[top.f] != -1) continue;
        parent[top.f] = top.s;
        for (auto x : graph[top.f]) dfs.emplace(x.f, top.f);
    }
    vvp dirGraph(n);
    for (ll i =0 ; i < n; i++)
    {
        for (auto x : graph[i]) if (x.f != parent[i]) dirGraph[i].pb(x);
    }
    ll last = 0;
    vp furtherest(n, p(-1,-1));
    findFurtherest(graph, weight, furtherest, 0);
    multiset<ll> values;
    v res(n, -1);
    vb visited(n, false);
    getRes(graph, weight, furtherest, 0, visited, res);
    multiset<ll,greater<ll>> reses;
    for (ll x : res) reses.insert(x);
    while (q--)
    {
        ll d, e;
        cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % w;
        weight[d] = e;
        ll cur = d;
        while (true)
        {
            furtherest[cur] = p(0, cur);
            for (auto x : dirGraph[cur])
            {
                furtherest[cur] = max(furtherest[cur], p(furtherest[x.f].f + weight[x.s], furtherest[x.f].s));
            }
            reses.erase(reses.find(res[cur]));
            ll curMaxi = furtherest[cur].f;
            v children;
            for (auto x : dirGraph[cur])
            {
                children.pb(furtherest[x.f].f + weight[x.s]);
            }
            sort(all(children),greater<ll>());
            if (children.size() >= 2) curMaxi = max(curMaxi, children[0] + children[1]);
            res[cur] = curMaxi;
            reses.insert(curMaxi);
            if (cur == 0) break;
            cur = parent[cur];
        }
        vb visited(n, false);
        last = *reses.begin();
        cout << last << "\n";
    }
    return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 13
• Subtask 3: 0 / 7
• Subtask 4: 0 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 27