Submission #898424

#	Time	Username	Problem	Language	Result	Execution time	Memory
898424		vjudge1	Tourism (JOI23_tourism)	C++17	10 / 100	61 ms	17396 KiB

tourism

#include <bits/stdc++.h>
using namespace std;



template<class T>
int len(T &a){
    return a.size();
}

using ll = long long;
using pii = pair<int,int>;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
string fileio = "";


mt19937 mt(time(nullptr));
const int mod = 1e9 + 7;
const int inf = 1e9;
const ll infl = 1e18;
const int maxn = 1e5 + 1;



struct Node{
    int mn;
};

struct Sparsemin{


    vector<vector<Node>> t;
    int n, logn;

    void init(int _n){
        n = _n;
        logn = 32 - __builtin_clz(n);
        t.assign(logn, vector<Node> (n));
    }

    Node merge(Node a, Node b){
        if(a.mn < b.mn) return a;
        return b;
    }

    void build(vector<int> &l){
        init(len(l));

        for(int i = 0; i < n; i ++){
            t[0][i] = {l[i]};
        }

        for(int j = 1; j < logn; j ++){
            for(int i = 0; i + (1 << (j - 1))  < n; i ++){
                t[j][i] = merge(t[j - 1][i], t[j - 1][i + (1 << (j - 1))]);
            }
        }
    }

    int get(int l, int r){
        int k = 31 - __builtin_clz(r - l + 1);
        return merge(t[k][l], t[k][l + (1 << k)]).mn;
    }
};



struct Sparsemax{
    vector<vector<Node>> t;
    int n, logn;

    void init(int _n){
        n = _n;
        logn = 32 - __builtin_clz(n);
        t.assign(logn, vector<Node> (n));
    }

    Node merge(Node a, Node b){
        if(a.mn > b.mn) return a;
        return b;
    }

    void build(vector<int> &l){
        init(len(l));

        for(int i = 0; i < n; i ++){
            t[0][i].mn = l[i];
        }

        for(int j = 1; j < logn; j ++){
            for(int i = 0; i + (1 << j) - 1 < n; i ++){
                t[j][i] = merge(t[j - 1][i], t[j - 1][i + (1 << (j - 1))]);
            }
        }
    }

    int get(int l, int r){
        int k = 31 - __builtin_clz(r - l + 1);
        //cout << l << ' ' << r << ' ' << k << endl;
        return merge(t[k][l], t[k][r - (1 << k) + 1]).mn;
    }
};



void solve(){
    int n, m, q; cin >> n >> m >> q;
    vector<int> sight(m);
    vector<vector<int>> g(n);

    for(int i = 1; i < n; i ++){
        int u, v; cin >> u >> v;
        u --; v --;
        g[u].push_back(v); g[v].push_back(u);
    }

    for(int i = 0; i < m; i ++){
        cin >> sight[i]; sight[i] --;
    }

    vector<pair<int,int>> qu(q);
    for(int i = 0; i < q; i ++){
        cin >> qu[i].ff >> qu[i].ss;
        qu[i].ff --; qu[i].ss --;
    }

    auto brute = [&]{vector<int> par(n);
        auto dfs = [&](auto &dfs, int i, int p = -1)->void{
            par[i] = p;
            for(auto u : g[i]){
                if(u == p) continue;
                dfs(dfs, u, i);
            }
        };
    
        for(auto [l, r] : qu){
            dfs(dfs, sight[l]);
            int cnt = 1;
            vector<int> vis(n);
            vis[sight[l]] = 1;
            for(int j = l + 1; j <= r; j ++){
                int cur = sight[j];
                while(vis[cur] == 0){
                    vis[cur] = 1;
                    //cout << "cur " << cur + 1 << endl;
                    cnt ++; cur = par[cur];
                }
            }
            cout << cnt << '\n';
        }
    };
    Sparsemax tmx;
    Sparsemin tmn;

    tmx.build(sight); tmn.build(sight);

    #ifdef LOCAL
    brute(); cout << "check: " << endl;
    #else
    if(n <= 2000) {brute(); return;}
    #endif

    for(auto [l, r] : qu){
        cout << tmx.get(l, r) - tmn.get(l, r) + 1 << '\n';
    }
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    auto start = chrono::high_resolution_clock::now();
    #ifndef LOCAL
    if(fileio.size()){
        freopen((fileio + ".in").c_str(), "r", stdin);
        freopen((fileio + ".out").c_str(), "w", stdout);
    }
    #endif
    int testcases = 1;
    #ifdef Tests
    cin >> testcases;
    #endif
    while(testcases --){
        solve();
        cout << '\n';
        #ifdef LOCAL
        cout << "_________________________" << endl;
        #endif
    }
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    
    cout << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
    return 0;
}

Compilation message (stderr)

tourism.cpp: In function 'int main()':
tourism.cpp:172:10: warning: variable 'start' set but not used [-Wunused-but-set-variable]
  172 |     auto start = chrono::high_resolution_clock::now();
      |          ^~~~~
tourism.cpp:175:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  175 |         freopen((fileio + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tourism.cpp:176:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  176 |         freopen((fileio + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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