Submission #938752

#	Time	Username	Problem	Language	Result	Execution time	Memory
938752		a_l_i_r_e_z_a	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	182 ms	50876 KiB

diameter

// In the name of God
// Hope is last to die
 
#include <bits/stdc++.h>
using namespace std;
 
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
#define pb push_back
// #define int long long
#define S second
#define F first
#define mp make_pair
#define smax(x, y) (x) = max((x), (y))
#define smin(x, y) (x) = min((x), (y))
#define all(x) (x).begin(), (x).end()
 
const int maxn = 1e5 + 5;
const int inf = 1e9 + 7;
struct D{
    ll ans, sum, mx, mn, ul, lv;
} node[maxn * 8];
ll n, q, W, w[maxn], in[maxn], out[maxn];
vector<pll> adj[maxn];
vector<ll> vec;
 
void dfs(int v, int p = -1){
    for(auto [u, e]: adj[v]){
        if(u == p) continue;
        in[e] = vec.size();
        vec.pb(w[e]);
        dfs(u, v);
        out[e] = vec.size();
        vec.pb(-w[e]);
    }
}
 
D merge(D l, D r){
    D res;
    res.ans = max(l.ans, max(r.ans, max(l.ul + r.mx + l.sum, l.mx + r.lv - l.sum)));
    res.sum = l.sum + r.sum;
    res.mx = max(l.mx, r.mx + l.sum);
    res.mn = min(l.mn, r.mn + l.sum);
    res.ul = max(l.ul, max(r.ul - l.sum, l.mx - 2 * (r.mn + l.sum)));
    res.lv = max(l.lv, max(r.lv - l.sum, -l.mn * 2 + r.mx + l.sum));
    return res;
}
 
void settle(int id, ll x){
    node[id].ans = abs(x);
    node[id].sum = x;
    node[id].mx = max(0ll, x);
    node[id].mn = min(0ll, x);
    node[id].ul = max(0ll, -2 * x);
    node[id].lv = max(0ll, x);
}
 
void build(int l = 0, int r = vec.size(), int id = 1){
    if(l == r - 1){
        settle(id, vec[l]);
        return;
    }
    int mid = (l + r) / 2;
    build(l, mid, id * 2);
    build(mid, r, id * 2 + 1);
    node[id] = merge(node[id * 2], node[id * 2 + 1]);
}
 
void upd(int p, ll x, int l = 0, int r = vec.size(), int id = 1){
    if(l == r - 1){
        settle(id, x);
        return;
    }
    int mid = (l + r) / 2;
    if(p < mid) upd(p, x, l, mid, id * 2);
    else upd(p, x, mid, r, id * 2 + 1);
    node[id] = merge(node[id * 2], node[id * 2 + 1]);
} 
 
int32_t main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
    cin >> n >> q >> W;
    for(int i = 0; i < n - 1; i++){
        int u, v; cin >> u >> v >> w[i];
        adj[u].pb(mp(v, i));
        adj[v].pb(mp(u, i));
    }
    dfs(1);
    build();
    ll last = 0;
    while(q--){
        ll d, e; cin >> d >> e;
        d = (d + last) % (n - 1);
        e = (e + last) % W;
        upd(in[d], e);
        upd(out[d], -e);
        last = node[1].ans;
        cout << last << '\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