Submission #689725

#	Time	Username	Problem	Language	Result	Execution time	Memory
689725		overwatch9	Dynamic Diameter (CEOI19_diameter)	C++17	24 / 100	1166 ms	2056 KiB

diameter

// subtask12
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
const int MAX_N = 5000 + 1;
vector <pair <int, ll>> adj[MAX_N];
struct edge {
    int a, b;
    ll w;
};
edge edges[MAX_N];
int node;
ll max_dis;
int N, Q;
ll W;
void dfs(int s, int p, ll dis) {
    if (dis > max_dis) {
        node = s;
        max_dis = dis;
    }
    for (auto i : adj[s]) {
        if (i.first == p)
            continue;
        dfs(i.first, s, dis + i.second);
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> N >> Q >> W;
    for (int i = 0; i < N-1; i++) {
        int a, b;
        ll w;
        cin >> a >> b >> w;
        adj[a].push_back({b, w});
        adj[b].push_back({a, w});
        edge tp;
        tp.a = a;
        tp.b = b;
        tp.w = w;
        edges[i] = tp;
    }
    for (int i = 1; i <= N; i++)
        sort(adj[i].begin(), adj[i].end());
    ll last = 0;
    while (Q--) {
        ll d;
        ll e;
        cin >> d >> e;
        d = (d + last) % (N-1);
        e = (e + last) % (W);
        int a = edges[d].a, b = edges[d].b;
        pair <int, ll> tp = {b, 0};
        auto x = lower_bound(adj[a].begin(), adj[a].end(), tp);
        x->second = e;
        tp = {a, 0};
        x = lower_bound(adj[b].begin(), adj[b].end(), tp);
        x->second = e;
        edges[d].w = e;
        max_dis = 0;
        dfs(1, 1, 0);
        max_dis = 0;
        dfs(node, node, 0);
        last = max_dis;
        cout << max_dis << '\n';
    }
}

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