제출 #501012

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
501012		InternetPerson10	Dynamic Diameter (CEOI19_diameter)	C++17	24 / 100	5063 ms	13380 KiB

diameter

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

vector<vector<pair<int, ll>>> adj;
vector<pair<int, int>> pa;
vector<pair<int, ll>> dist;
bool isStar = false;
multiset<ll> s;

void init(int n, int q, ll l, vector<int> u, vector<int> v, vector<ll> w) {
    pa.resize(n-1);
    adj.resize(n);
    s.insert(0);
    for(int i = 0; i < n-1; i++) {
        u[i]--; v[i]--;
        pa[i] = {u[i], v[i]};
        adj[u[i]].push_back({v[i], w[i]});
        adj[v[i]].push_back({u[i], w[i]});
    }
    if(adj[0].size() == n-1) { // subtask 3
        isStar = true;
        s.insert(0);
        for(int i = 0; i < n-1; i++) {
            s.insert(w[i]);
        }
    }
    for(int i = 0; i < n; i++) sort(adj[i].begin(), adj[i].end());
    dist.resize(n);
}

void dfs(int n, ll dis = 0, int par = -1) {
    dist[n] = {dis, n};
    for(auto ch : adj[n]) {
        if(ch.first == par) continue;
        dfs(ch.first, dis + ch.second, n);
    }
}

ll get_diameter(int d, ll e) {
    int x, y;
    tie(x, y) = pa[d];
    int l = 0, r = adj[x].size();
    while(l != r-1) {
        int mid = (l+r)/2;
        if(adj[x][mid].first <= y) l = mid;
        else r = mid; 
    }
    adj[x][l].second = e;
    l = 0; r = adj[y].size();
    while(l != r-1) {
        int mid = (l+r)/2;
        if(adj[y][mid].first <= x) l = mid;
        else r = mid; 
    }
    if(isStar) {
        auto it = s.find(adj[y][l].second);
        s.erase(it);
        s.insert(e);
        it = s.end();
        it--;
        ll ans = *it;
        it--;
        return ans + (*it);
    }
    adj[y][l].second = e;
    dfs(0);
    sort(dist.rbegin(), dist.rend());
    dfs(dist[0].second);
    sort(dist.rbegin(), dist.rend());
    return dist[0].first;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, q;
    ll l;
    cin >> n >> q >> l;
    vector<int> u(n-1), v(n-1);
    vector<ll> w(n-1);
    for(int i = 0; i < n-1; i++) {
        cin >> u[i] >> v[i] >> w[i];
    }
    init(n, q, l, u, v, w);
    ll last = 0;
    for(int i = 0; i < q; i++) {
        ll d, e;
        cin >> d >> e;
        d += last;
        d %= n-1;
        e += last;
        e %= l;
        last = get_diameter(d, e);
        cout << last << '\n';
    }
}

컴파일 시 표준 에러 (stderr) 메시지

diameter.cpp: In function 'void init(int, int, ll, std::vector<int>, std::vector<int>, std::vector<long long int>)':
diameter.cpp:22:22: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   22 |     if(adj[0].size() == n-1) { // subtask 3
      |        ~~~~~~~~~~~~~~^~~~~~

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