Submission #1019751

#	Time	Username	Problem	Language	Result	Execution time	Memory
1019751		Pacybwoah	Tourism (JOI23_tourism)	C++17	5 / 100	96 ms	856 KiB

tourism

#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<cassert>
#include<set>
#include<utility>
using namespace std;
const int k = 300;
vector<vector<int>> graph;
vector<int> in, dep, pos;
vector<vector<int>> anc;
int tst = 0;
void dfs(int node, int parent){
    in[++tst] = node;
    pos[node] = tst;
    anc[0][node] = parent;
    dep[node] = dep[parent] + 1;
    for(auto x: graph[node]){
        if(x == parent) continue;
        dfs(x, node);
    }
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m, q;
    cin >> n >> m >> q;
    assert(n <= 2000);
    in.resize(n + 1);
    dep.resize(n + 1);
    pos.resize(n + 1);
    anc.resize(18, vector<int>(n + 1));
    graph.resize(n + 1);
    int a, b;
    for(int i = 1; i < n; i++){
        cin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    dfs(1, 1);
    vector<int> vec(m + 1);
    for(int i = 1; i <= m; i++) cin >> vec[i], vec[i] = pos[vec[i]];
    vector<int> ans(q);
    for(int i = 1; i < 18; i++){
        for(int j = 1; j <= n; j++){
            anc[i][j] = anc[i - 1][anc[i - 1][j]];
        }
    }
    auto lca = [&](int u, int v){
        u = in[u], v = in[v];
        if(dep[u] < dep[v]) swap(u, v);
        for(int i = 17; i >= 0; i--){
            if((1 << i) & (dep[u] - dep[v])) u = anc[i][u];
        }
        for(int i = 17; i >= 0; i--){
            if(anc[i][u] != anc[i][v]) u = anc[i][u], v = anc[i][v];
        }
        if(u != v) u = anc[0][u], v = anc[0][v];
        return pos[u];
    };
    auto dist = [&](int u, int v){
        return dep[in[u]] + dep[in[v]] - 2 * dep[in[lca(u, v)]];
    };
    auto left = [&](int aa, int bb, int cc){
        return (dist(aa, bb) + dist(aa, cc) - dist(bb, cc)) / 2;
    };
    vector<vector<pair<pair<int, int>, int>>> queries(m / k + 1);
    for(int i = 0; i < q; i++){
        cin >> a >> b;
        queries[(a - 1) / k].push_back(make_pair(make_pair(a, b), i));
    }
    auto cmp = [&](pair<pair<int, int>, int> c, pair<pair<int, int>, int> d){
        return c.first.second < d.first.second;
    };
    for(int i = 0; i <= m / k; i++) sort(queries[i].begin(), queries[i].end(), cmp);
    for(auto &x: queries) for(auto &y: x) assert(y.first.second <= y.first.second);
    int lb = 0, now_lca = -1;
    for(auto &x: queries){
        lb += k;
        multiset<int> s;
        int cnt = 0, rb = lb, last_cnt = 0;
        auto add = [&](int node){
            if(s.empty()){
                now_lca = node;
                s.insert(node);
                cnt = 1;
                return;
            }
            auto iter = s.upper_bound(node);
            if(iter != s.end() && (*iter) == node){
                s.insert(node);
                return;
            }
            if(iter == s.begin()){
                cnt += left(node, (*iter), now_lca);
                now_lca = lca(node, now_lca);
                s.insert(node);
                return;
            }
            if(iter == s.end()){
                iter = prev(iter);
                //cout << node << " " << left(node, (*iter), now_lca) << "\n";
                //cout << node << " " << (*iter) << " " << now_lca << "\n";
                cnt += left(node, (*iter), now_lca);
                now_lca = lca(node, now_lca);
                s.insert(node);
                return;
            }
            int bf = (*prev(iter)), gf = (*iter);
            cnt += left(node, bf, gf);
            s.insert(node);
        };
        for(auto &y: x){
            a = y.first.first, b = y.first.second;
            while(b > rb){
                rb++;
                add(vec[rb]);
            }
            last_cnt = cnt;
            for(int i = a; i <= min(b, lb); i++){
                add(vec[i]);
            }
            ans[y.second] = cnt;
            cnt = last_cnt;
            for(int i = a; i <= min(b, lb); i++){
                s.erase(s.find(vec[i]));
            }
            //cout << cnt << "\n";
        }
    }
    for(int i = 0; i < q; i++) cout << ans[i] << "\n";
}
// g++ -std=c++17 pC.cpp -o run -fsanitize=undefined -fsanitize=address -Wall -Wextra -Wshadow
/*
7 6 2
1 2
1 3
2 4
2 5
3 6
3 7
2 3 6 4 5 7
1 3
4 6
*/

• Subtask 1: 5 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 7
• Subtask 4: 0 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 41