Submission #578801

#	Time	Username	Problem	Language	Result	Execution time	Memory
578801		talant117408	Dynamic Diameter (CEOI19_diameter)	C++17	49 / 100	2690 ms	30796 KiB

diameter

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

#define long                unsigned long 
#define pb                  push_back
#define mp                  make_pair
#define all(v)              (v).begin(),(v).end()
#define rall(v)             (v).rbegin(),(v).rend()
#define lb                  lower_bound
#define ub                  upper_bound
#define sz(v)               int((v).size())
#define do_not_disturb      ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl                '\n'

const int N = 1e5+7;
set <pair <int, ll>> graph[N];
vector <pair <pii, ll>> edges;
ll df, vf;
int n, q;
ll w;

void find_furthest(int v, int p, ll dist = 0) {
    if (dist > df) {
        df = dist;
        vf = v;
    }
    for (auto to : graph[v]) {
        if (to.first == p) continue;
        find_furthest(to.first, v, dist+to.second);
    }
}

void subtask3() {
    for (auto to : edges) {
        if (to.first.first != 1) {
            return;
        }
    }
    set <pair <ll, int>, greater <pair <ll, int>>> st;
    for (auto to : edges) {
        st.insert(mp(to.second, to.first.second));
    }
    ll last = 0;
    while (q--) {
        ll d, e;
        cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % w;
        auto &c = edges[d].second;
        auto b = edges[d].first.second;
        st.erase(st.find(mp(c, b)));
        c = e;
        st.insert(mp(c, b));
        ll ans = 0;
        ll cnt = 0;
        for (auto to : st) {
            ans += to.first;
            if (++cnt > 1) break;
        }
        cout << ans << endl;
        last = ans;
    }
    exit(0);
}

void subtask4() {
    vector <ll> ans_for(n+1);
    vector <pll> mx_child(n+1), dist_child(n+1);
    set <pair <ll, int>, greater <pair <ll, int>>> st;
    for (auto to : edges) {
        auto a = to.first.first;
        auto b = to.first.second;
        if (!(a*2 != b || a*2+1 != b)) {
            return;
        }
        if (a*2 == b) dist_child[a].first = to.second;
        else dist_child[a].second = to.second;
    }
    
    for (int i = 1; i <= n; i++) {
        if (sz(graph[i]) == 1) {
            int x = i;
            while (x) {
                if (x*2 <= n) mx_child[x].first = max(mx_child[x*2].first, mx_child[x*2].second)+dist_child[x].first;
                if (x*2+1 <= n) mx_child[x].second = max(mx_child[x*2+1].first, mx_child[x*2+1].second)+dist_child[x].second;
                x >>= 1;
            }
        }
    }
    for (int i = 1; i <= n; i++) {
        st.insert(mp(mx_child[i].first+mx_child[i].second, i));
    }
    
    ll last = 0;
    while (q--) {
        ll d, e;
        cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % w;
        auto a = edges[d].first.first, b = edges[d].first.second;
        int x = (b >> 1);
        if (a*2 == b) dist_child[a].first = e;
        else dist_child[a].second = e;
        while (x) {
            st.erase(st.find(mp(mx_child[x].first+mx_child[x].second, x)));
            if (x*2 <= n) mx_child[x].first = max(mx_child[x*2].first, mx_child[x*2].second)+dist_child[x].first;
            if (x*2+1 <= n) mx_child[x].second = max(mx_child[x*2+1].first, mx_child[x*2+1].second)+dist_child[x].second;
            st.insert(mp(mx_child[x].first+mx_child[x].second, x));
            x >>= 1;
        }
        cout << (*st.begin()).first << endl;
        last = (*st.begin()).first;
    }
    exit(0);
}

void solve() {
    cin >> n >> q >> w;
    for (int i = 0; i < n-1; i++) {
        int a, b;
        ll c;
        cin >> a >> b >> c;
        if (a > b) swap(a, b);
        edges.pb(mp(mp(a, b), c));
        graph[a].insert(mp(b, c));
        graph[b].insert(mp(a, c));
    }
    
    
    if (n <= 5000) {
        ll last = 0;
        while (q--) {
            ll d, e;
            cin >> d >> e;
            d = (d + last) % (n - 1);
            e = (e + last) % w;
            auto a = edges[d].first.first, b = edges[d].first.second;
            auto &c = edges[d].second;
            graph[a].erase(graph[a].find(mp(b, c)));
            graph[b].erase(graph[b].find(mp(a, c)));
            c = e;
            graph[a].insert(mp(b, c));
            graph[b].insert(mp(a, c));
            df = vf = 0;
            find_furthest(1, 1);
            df = 0;
            find_furthest(vf, vf);
            cout << df << endl;
            last = df;
        }
        return;
    }
    subtask3();
    subtask4();
}

int main() {
    do_not_disturb
    
    int t = 1;
    //~ cin >> t;
    while (t--) {
        solve();
    }
    
    return 0;
}
/*

*/

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