Submission #1280935

#	Time	Username	Problem	Language	Result	Execution time	Memory
1280935		Icelast	Tourism (JOI23_tourism)	C++20	28 / 100	5092 ms	25480 KiB

tourism

#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 4e18+9;
struct Tree{
    int n, root;
    vector<int> depth, head, sz, pa;
    vector<int> f;
    Tree(int n, int root, vector<vector<int>> &adj): n(n), root(root){
        depth.resize(n+1, -1);
        head.resize(n+1);
        sz.resize(n+1, 0);
        pa.resize(n+1, -1);
        auto rootTree = [&](auto rootTree, int u, int p) -> void{
            depth[u] = depth[p]+1;
            pa[u] = p;
            sz[u] = 1;
            for(int v : adj[u]){
                if(v == p) continue;
                rootTree(rootTree, v, u);
                sz[u] += sz[v];
            }
        };
        rootTree(rootTree, root, 0);
        auto decompose = [&](auto decompose, int u, int h) -> void{
            head[u] = h;
            int heavy = -1;
            for(int v : adj[u]){
                if(v == pa[u]) continue;
                if(heavy == -1 || sz[heavy] < sz[v]) heavy = v;
            }
            if(heavy != -1) decompose(decompose, heavy, h);
            for(int v : adj[u]){
                if(v == pa[u] || v == heavy) continue;
                decompose(decompose, v, v);
            }
        };
        decompose(decompose, root, root);
        f = [&]{
            vector<array<int, 2>> first(n+1);
            vector<array<int, 2>> second(n+1);
            function<void(int, int)> dfs0 = [&](int u, int p) {
                first[u] = second[u] = {0, -1};
                for (int v : adj[u]) {
                    if (v == p) {
                        continue;
                    }
                    dfs0(v, u);
                    auto fetch = first[v];
                    fetch[0] += 1;
                    fetch[1] = v;
                    if (fetch > first[u]) {
                        swap(fetch, first[u]);
                    }
                    if (fetch > second[u]) {
                        swap(fetch, second[u]);
                    }
                }
            };
            dfs0(1, 0);

            function<void(int, int)> dfs = [&](int u, int p) {
                for (int v : adj[u]) {
                    if (v == p) {
                        continue;
                    }
                    auto fetch = first[u][1] == v ? second[u] : first[u];
                    fetch[0] += 1;
                    fetch[1] = u;
                    if (fetch > first[v]) {
                        swap(fetch, first[v]);
                    }
                    if (fetch > second[v]) {
                        swap(fetch, second[v]);
                    }
                    dfs(v, u);
                }
            };
            dfs(1, 0);
            vector<int> f(n+1);
            for (int u = 1; u <= n; u++) {
                f[u] = first[u][0];
            }
            return f;
        }();
    };
    int lca(int u, int v){
        for(; head[u] != head[v]; v = pa[head[v]]){
            if(depth[head[u]] > depth[head[v]]) swap(u, v);
        }
        if(depth[u] > depth[v]) swap(u, v);
        return u;
    }
    int dist(int u, int v) {
        return depth[u]+depth[v]-2*depth[lca(u, v)];
    }
};
struct que{
    int l, r, id;
};
void solve(){
    int n, m, Q;
    cin >> n >> m >> Q;
    vector<vector<int>> adj(n+1);
    for(int i = 1; i < n; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    vector<int> b(m+1);
    for(int i = 1; i <= m; i++){
        cin >> b[i];
    }
    vector<que> q;
    for(int i = 1; i <= Q; i++){
        int l, r;
        cin >> l >> r;
        q.push_back({l, r, i});
    }
    Tree Y(n, 1, adj);
    vector<int> tin(n+1), node(n+1);
    int timer = 0;
    auto dfs = [&](auto dfs, int u, int p) -> void{
        timer++;
        tin[u] = timer;
        node[timer] = u;
        for(int v : adj[u]){
            if(v == p) continue;
            dfs(dfs, v, u);
        }
    };
    dfs(dfs, 1, 0);
    int B = 400;
    sort(q.begin(), q.end(), [&](que a, que b){
        if(a.l/B != b.l/B){
            return a.l < b.l;
        }
        return a.r < b.r;
    });
    set<int> s;
    int ans = 0;
    vector<int> cnt(n+1, 0);
    auto add = [&](int u) -> void{
        cnt[u]++;
        if(cnt[u] > 1){
            return;
        }
        int x = tin[u];
        if(s.size() >= 1){
            auto it = s.lower_bound(x);
            if(it == s.begin()){
                it = prev(s.end());
            }else{
                it--;
            }
            int v1 = node[*it];
            it++;
            if(it == s.end()) it = s.begin();
            int v2 = node[*it];
            ans -= Y.dist(v1, v2);
            ans += Y.dist(v1, u);
            ans += Y.dist(u, v2);
        }
        s.insert(x);
    };
    auto del = [&](int u) -> void{
        cnt[u]--;
        if(cnt[u] > 0){
            return;
        }
        int x = tin[u];
        if(s.size() >= 1){
            auto it = s.lower_bound(x);
            if(it == s.begin()){
                it = prev(s.end());
            }else{
                it--;
            }
            int v1 = node[*it];
            it++;
            if(it == s.end()) it = s.begin();
            it++;
            if(it == s.end()) it = s.begin();
            int v2 = node[*it];
            ans += Y.dist(v1, v2);
            ans -= Y.dist(v1, u);
            ans -= Y.dist(u, v2);
        }
        s.erase(x);
    };
    vector<int> res(Q+1);
    int l = 1, r = 0;
    for(auto it : q){
        int L = it.l, R = it.r, id = it.id;
        while(r < R){
            r++;
            add(b[r]);
        }
        while(r > R){
            del(b[r]);
            r--;
        }
        while(l < L){
            del(b[l]);
            l++;
        }
        while(l > L){
            l--;
            add(b[l]);
        }
        res[id] = ans/2 + 1;
    }
    for(int i = 1; i <= Q; i++){
        cout << res[i] << "\n";
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
}

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