Submission #1098944

#	Time	Username	Problem	Language	Result	Execution time	Memory
1098944		steveonalex	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	578 ms	71088 KiB

diameter

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }
 
const ll N = 1e5 + 69, LOG_N = 17, BLOCK = 600;
ll n, q;
vector<pair<ll, ll>> graph[N];
ll w[N]; 
ll parent[N];
ll l[N], r[N], pos[N * 2], dfs_cnt = 0, rmq[LOG_N + 1][N * 2];

void init_lca(ll u, ll p){
    l[u] = r[u] = ++dfs_cnt;
    rmq[0][dfs_cnt] = l[u];
    pos[dfs_cnt] = u;

    for(pair<ll,ll> v: graph[u]) if (v.first != p){
        parent[v.second] = v.first;

        init_lca(v.first, u);

        r[u] = ++dfs_cnt;
        rmq[0][dfs_cnt] = l[u];
        pos[dfs_cnt] = u;
    }
}

void init_rmq(){
    for(ll j = 1; MASK(j) <= n * 2 - 1; ++j)
    for(ll i = 1; i + MASK(j) - 1 <= n * 2 - 1; ++i){
        rmq[j][i] = min(rmq[j-1][i], rmq[j-1][i + MASK(j-1)]);
    }
}

ll LCA(ll u, ll v){
    u = l[u], v = l[v];
    if (u > v) swap(u, v);
    ll j = logOf(v - u + 1);
    return pos[min(rmq[j][u], rmq[j][v - MASK(j) + 1])];
}

ll h[N * 2], s_h[N * 2 / BLOCK + 1];

void update_h(ll l, ll r, ll v){
    ll b_l = l / BLOCK, b_r = r / BLOCK;
    if (b_l == b_r){
        for(ll i = l; i <= r; ++i) h[i] += v;
    }
    else{
        for(ll i = l; i < (b_l + 1) * BLOCK; ++i) h[i] += v;
        for(ll i = b_r * BLOCK; i <= r; ++i) h[i] += v;
        for(ll i = b_l + 1; i <= b_r - 1; ++i) s_h[i] += v;
    }
}

ll get_h(ll i){
    i = l[i];
    return h[i] + s_h[i / BLOCK];
}

ll get_sum_path(ll u, ll v){
    return get_h(u) + get_h(v) - 2 * get_h(LCA(u, v));
}

struct SegmentTree{
    struct Node{
        ll u, v;
        ll w;
        Node(ll u = 0, ll v = 0, ll w = 0): u(u), v(v), w(w){
        }

        bool operator < (Node x) const {
            return w < x.w;
        }
        bool operator > (Node x) const {
            return w > x.w;
        }
    };

    Node combine(Node a, Node b){
        if (a.u == 0) return b;
        if (b.u == 0) return a;
        Node ans = max(a, b);
        for(ll i = 0; i <= 1; ++i) {
            for(ll j = 0; j <= 1; ++j){
                Node cur = Node(a.u, b.u, get_sum_path(a.u, b.u));
                maximize(ans, cur);
                swap(b.u, b.v);
            }
            swap(a.u, a.v);
        } 
        return ans;
    }

    ll n;
    vector<Node> a;

    SegmentTree(ll _n){
        n = _n;
        a.resize(n * 4 + 4, Node());
        build_tree(1, n, 1);
    }

    void build_tree(ll l, ll r, ll id){
        if (l == r) {a[id] = Node(pos[l], pos[l], 0); return;}
        ll mid = (l + r) >> 1;
        build_tree(l, mid, id * 2); build_tree(mid + 1, r, id * 2 + 1);
        a[id] = combine(a[id * 2], a[id * 2 + 1]);
    }

    void update(ll u, ll v, ll l, ll r, ll id){
        if (u <= l && r <= v) return;
        ll mid = (l + r) >> 1;
        if (u <= mid) update(u, v, l, mid, id * 2);
        if (v > mid) update(u, v, mid + 1, r, id * 2 + 1);
        a[id] = combine(a[id * 2], a[id * 2 + 1]);
    }

    void update(ll l, ll r){update(l, r, 1, n, 1);}

    ll get(){return a[1].w;}
};
 
int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    clock_t start = clock();
 
    cin >> n >> q >> w[0];
    for(int i= 1; i<n; ++i){
        int u, v; cin >> u >> v >> w[i];
        graph[u].push_back({v, i});
        graph[v].push_back({u, i});
    }

    init_lca(1, 0);
    init_rmq();

    for(int i = 1; i<n; ++i) {
        int u = parent[i];
        update_h(l[u], r[u], w[i]);
    }
    SegmentTree st(n * 2 - 1);

    ll last = 0;
    for(int it = 0; it < q; ++it){
        ll d, e; cin >> d >> e;
        d = (d + last) % (n-1) + 1;
        e = (e + last) % w[0];

        int u = parent[d];
        ll diff = e - w[d];
        w[d] = e;
        update_h(l[u], r[u], diff);

        st.update(l[u], r[u]);
        last = st.get();

        cout << last << "\n";

    }
 
    cerr << "Time elapsed: " << clock() - start << " ms\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