Submission #1099096

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099096		anhthi	Dynamic Diameter (CEOI19_diameter)	C++14	100 / 100	851 ms	55716 KiB

diameter

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)

template <class X, class Y>
    inline bool maximize(X &x, Y y) {
        return (x < y ? x = y, true : false);
    }

template <class X, class Y>
    inline bool minimize(X &x, Y y) {
        return (x > y ? x = y, true : false);
    }

template <class X>
    inline void compress(vector<X> &a) {
        sort(all(a));
        a.resize(unique(all(a)) - a.begin());
    }

int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
    return l + abs((ll) rng()) % (r - l + 1);
}

const ll oo = (ll) 1e17;
const int inf = (ll) 1e9 + 7, mod = (ll) 1e9 + 7;

const int N = 1e5 + 5, BASE = 307, LOG = 18;

void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }

int n, Q; ll W;
struct Edge {
    int u, v; ll w;
    void input() {
        cin >> u >> v >> w;
    }
} e[N];

vector<pair<int, int>> g[N];
namespace LCA {
    int timer = 0;

    ll dist[N];
    int d[N], in[N], out[N], tour[N << 1];
        
    void dfs(int u = 1, int p = 0) {
        in[u] = ++timer;
        tour[timer] = u;
        for (pair<int, int> i : g[u]) {
            int v = i.first;
            if (v == p) continue;
            d[v] = d[u] + 1;
            dist[v] = dist[u] + e[i.second].w;
            dfs(v, u);
            tour[++timer] = u; 
        }
        out[u] = timer;
    }

    int rmq[N << 1][LOG + 5];

    int min_rmq(int u, int v) {
        return d[u] < d[v] ? u : v;
    }
    void init_rmq() {
        rep(i, timer) rmq[i][0] = tour[i];
        rep(j, LOG) {
            rep(i, timer - MASK(j) + 1) {
                rmq[i][j] = min_rmq(rmq[i][j-1], rmq[i + MASK(j-1)][j-1]);
            }
        }
        return;
    }
    int lca(int u, int v) {
        u = in[u]; v = in[v];
        if (u > v) swap(u, v);
        int h = lg(v - u + 1);
        return min_rmq(rmq[u][h], rmq[v - MASK(h) + 1][h]);
    }
} using namespace LCA;

namespace CTDL {

    ll bit[N << 1];
    void upd(int p, ll d) {
        for (; p <= timer; p += p & -p)
            bit[p] += d;
        return;
    }
    void upd_range(int l, int r, ll d) {
        upd(l, +d);
        upd(r + 1, -d);
    }
    ll get(int p) {
        ll ans = 0;
        for (; p > 0; p -= p & -p)
            ans += bit[p];
        return ans;
    }
    ll getDist(int u, int v) {
        return get(in[u]) + get(in[v]) - 2 * get(in[lca(u, v)]);
    }

    struct node {
        ll ans;
        int u, v;
        node(ll a = 0, int b = 0, int c = 0) {
            ans = a;
            u = b; v = c;
        }
        void trans(int _u, int _v) {
            if (maximize(ans, getDist(_u, _v))) {
                u = _u; v = _v;
            }
        }
        void debug() {
            cout << ans << ' ' << u << ' ' << v << '\n';
        }
    };
    node st[(N << 3) + 5];

    node combine(node &x, node &y) {
        if (!x.u) return y;
        if (!y.u) return x;
        node res = (x.ans < y.ans ? y : x);
        res.trans(x.u, y.u); res.trans(x.u, y.v);
        res.trans(x.v, y.u); res.trans(x.v, y.v);
        return res;
    }

    void build(int i, int l, int r) {
        if (l == r) {
            st[i] = node(0, tour[l], tour[l]);
        }   
        else {
            int m = (l + r) >> 1;
            build(2 * i, l, m);
            build(2 * i + 1, m + 1, r);
            st[i] = combine(st[2 * i], st[2 * i + 1]);
        }
        return;
    }
    void build() { return build(1, 1, timer); }

    void upd(int i, int l, int r, int u, int v) {
        if (l > v || r < u) return;
        if (l >= u && r <= v) return;
        int m = (l + r) >> 1;
        upd(2 * i, l, m, u, v);
        upd(2 * i + 1, m + 1, r, u, v);
        st[i] = combine(st[2 * i], st[2 * i + 1]);
    }

    void upd(int u, int v) {
        return upd(1, 1, timer, u, v);
    }

    ll solve() { return st[1].ans; }

} using namespace CTDL;

signed main(void) {

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    // freopen("input.inp", "r", stdin);

    cin >> n >> Q >> W;
    rep(i, n - 1) {
        e[i].input();
        g[e[i].u].pb(mp(e[i].v, i));
        g[e[i].v].pb(mp(e[i].u, i));
    }

    dfs();
    init_rmq();
    rep(i, n - 1) {
        if (d[e[i].u] > d[e[i].v])
            swap(e[i].u, e[i].v);
    }
    rep(i, timer) {
        upd_range(i, i, dist[tour[i]]);
    }

    build();
    ll lst = 0;

    rep(_, Q) {
        int d; ll g;
        cin >> d >> g;

        g = (g + lst) % W;
        d = (d + lst) % (n - 1) + 1;
            
        Edge &cur = e[d];
        ll change = g - cur.w;      
        cur.w = g;

        upd_range(in[cur.v], out[cur.v], change);
        upd(in[cur.v], out[cur.v]);

        cout << (lst = solve()) << '\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