제출 #518612

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
518612		Monarchuwu	Dynamic Diameter (CEOI19_diameter)	C++17	49 / 100	1426 ms	17596 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';
        }
    }
}

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();
}
/**  /\_/\
 *  (= ._.)
 *  / >0  \>1
**/

컴파일 시 표준 에러 (stderr) 메시지

diameter.cpp: In function 'int main()':
diameter.cpp:136:21: warning: unused variable 'u' [-Wunused-variable]
  136 |     for (int i = 1, u, v; i < n; ++i) {
      |                     ^
diameter.cpp:136:24: warning: unused variable 'v' [-Wunused-variable]
  136 |     for (int i = 1, u, v; i < n; ++i) {
      |                        ^
diameter.cpp:144:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  144 |     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