제출 #518631

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
518631		Monarchuwu	Dynamic Diameter (CEOI19_diameter)	C++17	49 / 100	1454 ms	19516 KiB

diameter

#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
#define all(x) x.begin(), x.end()
using namespace std;
typedef long long ll;

typedef pair<int, ll> pil;
#define ff first
#define ss second

const int N = 1e5 + 9;
int n, q;
ll w, c;
vector<int> g[N];
struct Edge {
    int u, v;
    ll w;
    int operator()(int x) { return u ^ v ^ x; }
} e[N];

namespace subtask12 {
    vector<ll> a[N];
    void dfs(int u, int p) {
        a[u].assign(2, 0);
        for (int id : g[u]) if (p != id) {
            int v = e[id](u);
            dfs(v, id);
            a[u].push_back(a[v][0] + e[id].w);
        }
        sort(all(a[u]), greater<ll>());
    }
    ll gogo() {
        dfs(1, 0);
        ll ans(0);
        for (int i = 1; i <= n; ++i)
            ans = max(ans, a[i][0] + a[i][1]);
        return ans;
    }
    void solve() {
        int d;
        ll ee, last(0); while (q--) {
            cin >> d >> ee;
            d = (d + last) % (n - 1);
            ee = (ee + last) % w;

            e[d + 1].w = ee;
            last = gogo();
            cout << last << '\n';
        }
    }
}

namespace subtask3 {
    void solve() {
        multiset<int, greater<int>> s;
        for (int i = 1; i < n; ++i)
            s.insert(e[i].w);

        int d, ee, last(0); while (q--) {
            cin >> d >> ee;
            d = (d + last) % (n - 1);
            ee = (ee + last) % w;

            s.erase(s.find(e[d + 1].w));
            s.insert(e[d + 1].w = ee);
            last = *s.begin() + *next(s.begin());

            cout << last << '\n';
        }
    }
}

namespace subtask4 {
    bool check() {
        for (int i = 1; i < n; ++i)
            if (e[i].v / 2 != e[i].u) return false;
        return true;
    }

    struct Node {
        ll path, diam;
    } seg[1 << 18];
    ll wei[N];

    void build(int u) {
        if (u > n) return;
        if (u * 2 > n) seg[u].path = seg[u].diam = wei[u];
        else {
            int u1 = u << 1, u2 = u1 | 1;
            build(u1);
            build(u2);
            seg[u].path = max(seg[u1].path, seg[u2].path) + wei[u];
            seg[u].diam = max({ seg[u1].diam, seg[u2].diam, seg[u1].path + seg[u2].path });
        }
    }

    void upd(int u) {
        if (u * 2 > n) seg[u].path = seg[u].diam = wei[u];
        else {
            int u1 = u << 1, u2 = u1 | 1;
            seg[u].path = max(seg[u1].path, seg[u2].path) + wei[u];
        }

        for (u >>= 1; u; u >>= 1) {
            int u1 = u << 1, u2 = u1 | 1;
            seg[u].path = max(seg[u1].path, seg[u2].path) + wei[u];
            seg[u].diam = max({ seg[u1].diam, seg[u2].diam, seg[u1].path + seg[u2].path });
        }
    }

    void solve() {
        wei[1] = 0;
        for (int i = 1; i < n; ++i) wei[e[i].v] = e[i].w;
        build(1);

        int d;
        ll ee, last(0); while (q--) {
            cin >> d >> ee;
            d = (d + last) % (n - 1);
            ee = (ee + last) % w;

            wei[e[d + 1].v] = ee;
            upd(e[d + 1].v);
            last = seg[1].diam;

            cout << last << '\n';
        }
    }
}

namespace subtask5 {
    int tme = 0, tin[N], tout[N];
    int par[N];
    ll wei[N];
    void dfs(int u) {
        tin[u] = ++tme;
        for (int id : g[u]) {
            int v = e[id](u);
            if (v == par[u]) continue;

            par[v] = u;
            wei[v] = e[id].w;
            dfs(v);
        }
        tout[u] = tme;
    }

    struct Node {
        ll ma, laz;
        Node() : ma(0), laz(0) {}
    } seg[1 << 18];

    void upd(int u, int l, int r, int a, int b, ll v) {
        if (a <= l && r <= b) {
            seg[u].ma += v;
            seg[u].laz += v;
            return;
        }
        int m = (l + r) >> 1, u1 = u << 1, u2 = u1 | 1;
        if (seg[u].laz) {
            seg[u1].ma += seg[u].laz;
            seg[u1].laz += seg[u].laz;
            seg[u2].ma += seg[u].laz;
            seg[u2].laz += seg[u].laz;
            seg[u].laz = 0;
        }
        if (a <= m) upd(u1, l, m, a, b, v);
        if (m < b) upd(u2, m + 1, r, a, b, v);
        seg[u].ma = max(seg[u1].ma, seg[u2].ma);
    }

    ll qry(int u, int l, int r, int a, int b) {
        if (b < l || r < a) return 0;
        if (a <= l && r <= b) return seg[u].ma;

        int m = (l + r) >> 1, u1 = u << 1, u2 = u1 | 1;
        if (seg[u].laz) {
            seg[u1].ma += seg[u].laz;
            seg[u1].laz += seg[u].laz;
            seg[u2].ma += seg[u].laz;
            seg[u2].laz += seg[u].laz;
            seg[u].laz = 0;
        }
        return max(qry(u1, l, m, a, b), qry(u2, m + 1, r, a, b));
    }

    ll sum_t[N];
    void solve() {
        dfs(1);
        for (int i = 2; i <= n; ++i)
            upd(1, 1, n, tin[i], tout[i], wei[i]);

        multiset<ll, greater<ll>> s;
        vector<int> a;
        s.insert(0);
        for (int id : g[1]) {
            int v = e[id](1);
            a.push_back(v);

            sum_t[v] = qry(1, 1, n, tin[v], tout[v]);
            s.insert(sum_t[v]);
        }
        sort(all(a));

        int d, u, v, p;
        ll ee, last(0); while (q--) {
            cin >> d >> ee;
            d = (d + last) % (n - 1);
            ee = (ee + last) % w;

            u = e[d + 1].u, v = e[d + 1].v;
            if (par[u] == v) swap(u, v);
            // par[v] == u
            upd(1, 1, n, tin[v], tout[v], ee - wei[v]);
            wei[v] = ee;

            p = *prev(upper_bound(all(a), v));
            s.erase(s.find(sum_t[p]));

            sum_t[p] = qry(1, 1, n, tin[p], tout[p]);
            s.insert(sum_t[p]);

            last = *s.begin() + *next(s.begin());
            cout << last << '\n';
        }
    }
}

int main() {
    cin.tie(NULL)->sync_with_stdio(false);
    cin >> n >> q >> w;
    for (int i = 1, u, v; i < n; ++i) {
        cin >> e[i].u >> e[i].v >> e[i].w;
        if (e[i].u > e[i].v) swap(e[i].u, e[i].v);
        g[e[i].u].push_back(i);
        g[e[i].v].push_back(i);
    }

    if (n <= 5000 && q <= 5000) subtask12::solve();
    else if (g[1].size() == n - 1) subtask3::solve();
    else if (subtask4::check()) subtask4::solve();
    else subtask5::solve();
}
/**  /\_/\
 *  (= ._.)
 *  / >0  \>1
**/

컴파일 시 표준 에러 (stderr) 메시지

diameter.cpp: In function 'int main()':
diameter.cpp:234:21: warning: unused variable 'u' [-Wunused-variable]
  234 |     for (int i = 1, u, v; i < n; ++i) {
      |                     ^
diameter.cpp:234:24: warning: unused variable 'v' [-Wunused-variable]
  234 |     for (int i = 1, u, v; i < n; ++i) {
      |                        ^
diameter.cpp:242:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  242 |     else if (g[1].size() == n - 1) subtask3::solve();
      |              ~~~~~~~~~~~~^~~~~~~~

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