Submission #876945

#	Time	Username	Problem	Language	Result	Execution time	Memory
876945		Cookie	Dynamic Diameter (CEOI19_diameter)	C++14	100 / 100	1016 ms	69828 KiB

diameter

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
ifstream fin("ANTNEST.INP");
ofstream fout("ANTNEST.OUT");
#define sz(a) (int)a.size()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
#define mpp make_pair
const ld PI = 3.14159265359;
//using u128 = __uint128_t;
//const int x[4] = {1, -1, 0, 0};
//const int y[4] = {0, 0, 1, -1};
const ll mod = 1e9 + 7;
const int mxn = 2e5 + 5, mxq = 2e5 + 5, sq = 350, mxv = 5e5 + 5;
const ll inf = 1e18;
const ld prec = 1e-9;

int n, q;
ll MX;
struct BIT{
    ll bit[mxn + 1];
    void upd(int p, ll v){
        while(p <= n){
            bit[p] += v; p += p & (-p);
        }
    }
    ll get(int p){
        ll ans = 0;
        while(p){
            ans += bit[p]; p -= p & (-p);
        }
        return(ans);
    }
    ll query(int l, int r){
        return(get(r) - get(l - 1));
    }
};
BIT bit;
pii up[mxn + 1][19];
int tin[mxn + 1], tout[mxn + 1], siz[mxn + 1], dep[mxn + 1], tonode[mxn + 1], tt = 0, eu = 0, eutin[mxn + 1];
int u[mxn + 1], v[mxn + 1];
ll w[mxn + 1];
vt<pll>adj[mxn + 1];
pii getmn(int l, int r){
    int lg = __lg(r - l + 1);
    return(min(up[l][lg], up[r - (1 << lg) + 1][lg]));
}
int lca(int u, int v){
    if(tin[u] > tin[v])swap(u, v);
    return(getmn(tin[u], tin[v]).se);
}
ll getdist(int u, int v){
    return(bit.get(eutin[u]) + bit.get(eutin[v]) - 2 * bit.get(eutin[lca(u, v)]));
}
void dfs(int s, int pre){
    tin[s] = ++tt; tonode[tt] = s; siz[s] = 1;
    eutin[s] = ++eu;
    for(auto [i, w]: adj[s]){
        if(i != pre){
            dep[i] = dep[s] + 1;
            dfs(i, s); siz[s] += siz[i];
            tonode[++tt] = s;
        }
    }
    tout[s] = tt;
}
struct Node{
    int u, v; ll d;
    Node(){
        
    }
    Node(int _u, int _v, ll _d){
        u = _u; v = _v; d = _d;
    }
    friend bool operator <(Node a, Node b){
        return(a.d < b.d);
    }
    friend Node operator +(Node a, Node b){
        Node res = Node(-1, -1, -1);
        res = max(res, a); res = max(res, b);
        res = max(res, Node(a.u, b.u, getdist(a.u, b.u)));
        res = max(res, Node(a.u, b.v, getdist(a.u, b.v)));
        res = max(res, Node(a.v, b.u, getdist(a.v, b.u)));
        res = max(res, Node(a.v, b.v, getdist(a.v, b.v)));
        return(res);
    }
};
Node st[4 * mxn + 1];
void build(int nd, int l, int r){
    if(l == r){
        st[nd] = Node(tonode[l], tonode[l], 0);
        return;
    }
    int mid = (l + r) >> 1;
    build(nd << 1, l, mid); build(nd << 1 | 1, mid + 1, r);
    st[nd] = st[nd << 1] + st[nd << 1 | 1];
}
void upd(int nd, int l, int r, int ql, int qr){     
    if(ql > r || qr < l)return;
    if(ql <= l && qr >= r)return;
    int mid = (l + r) >> 1;
    upd(nd << 1, l, mid, ql, qr); upd(nd << 1 | 1, mid + 1, r, ql, qr);
    st[nd] = st[nd << 1] + st[nd << 1 | 1];
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> q >> MX;
    for(int i = 0; i < n - 1; i++){
        cin >> u[i] >> v[i] >> w[i];
        adj[u[i]].pb(mpp(v[i], w[i])); adj[v[i]].pb(mpp(u[i], w[i]));
    }
    dfs(1, -1);
    for(int i = 0; i < n - 1; i++){
       
        if(dep[u[i]] > dep[v[i]])swap(u[i], v[i]);
        bit.upd(eutin[v[i]], w[i]); bit.upd(eutin[v[i]] + siz[v[i]], -w[i]); 
    }
    for(int i = 1; i <= tt; i++)up[i][0] = mpp(dep[tonode[i]], tonode[i]);
    for(int i = 1; i < 19; i++){
        for(int j = 1; j + (1 << i) - 1 <= tt; j++){
            up[j][i] = min(up[j][i - 1], up[j + (1 << (i - 1))][i - 1]);
        }
    }
    
    build(1, 1, tt);
    
    
    ll last = 0;
    while(q--){
        ll d, e; cin >> d >> e; d = (d + last) % (n - 1); e = (e + last) % MX;
        bit.upd(eutin[v[d]], e - w[d]); bit.upd(eutin[v[d]] + siz[v[d]], -(e - w[d]));
        upd(1, 1, tt, tin[v[d]], tout[v[d]]);
        last = st[1].d; w[d] = e;
        cout << last << "\n";
        
    }
    return(0);
}

Compilation message (stderr)

diameter.cpp: In function 'void dfs(int, int)':
diameter.cpp:68:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   68 |     for(auto [i, w]: adj[s]){
      |              ^

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