Submission #768831

#	Time	Username	Problem	Language	Result	Execution time	Memory
768831		fanwen	Synchronization (JOI13_synchronization)	C++17	100 / 100	251 ms	24956 KiB

synchronization

/**
 *      author : pham van sam 
 *      created : 28 June 2023 (Wednesday)
 **/

#include <bits/stdc++.h>

using namespace std;

#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for (int i = 0, _n = n; i < _n; ++i)
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define FORE(it, s) for (__typeof(s.begin()) it = (s).begin(); it != (s).end(); ++it)

template <typename U, typename V> bool maximize(U &A, const V &B) { return (A < B) ? (A = B, true) : false; }
template <typename U, typename V> bool minimize(U &A, const V &B) { return (A > B) ? (A = B, true) : false; }

void you_make_it(void);

signed main() {

    #define TASK "synchronization"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    auto start_time = chrono::steady_clock::now();

    int test = 1;
    // cin >> test;
    for (int i = 1; i <= test; ++i) {
        you_make_it();
        // cout << '\n';
    }

    auto end_time = chrono::steady_clock::now();

    cerr << "\nExecution time : " << chrono::duration_cast <chrono::milliseconds> (end_time - start_time).count() << "[ms]" << endl;

    return (0 ^ 0);
}

template <class T> struct Fenwick_Tree {
    vector<T> bit;
    int n;
    Fenwick_Tree(int _n = 0) : n(_n), bit(_n + 5){}
    
    void clear() { fill(bit.begin(), bit.end(), T(0)); }

    void update(int u, T val) {
        for (; u <= n; u += u & -u) bit[u] += val;
    }
    
    T get(int u) {
        T ans = 0;
        for (; u; u -= u & -u) ans += bit[u];
        return ans; 
    }
    
    T get(int l, int r) {
        return get(r) - get(l - 1);
    }
};

const int MAXN = 1e5 + 2;

Fenwick_Tree <int> bit;

int N, M, Q, anc[MAXN][21], active[MAXN];
vector <int> adj[MAXN];
int infor[MAXN], last_sync[MAXN];
pair <int, int> edges[MAXN];
int time_in[MAXN], time_out[MAXN];

void dfs(int u, int p) {
    anc[u][0] = p;
    FOR(i, 1, 20) anc[u][i] = anc[anc[u][i - 1]][i - 1];
    static int run = 0;
    infor[u] = 1;
    time_in[u] = ++run;
    for (auto v : adj[u]) if(v != p) dfs(v, u);
    time_out[u] = run;
}

int find_anc(int u) {
    int lca = u;
    FORD(i, 20, 0) if(anc[lca][i] != 0 && bit.get(time_in[anc[lca][i]]) == bit.get(time_in[u])) {
        lca = anc[lca][i];
    }
    return lca;
}

void you_make_it() {
    cin >> N >> M >> Q;
    FOR(i, 1, N - 1) {
        int u, v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
        edges[i] = make_pair(u, v);
    }
    dfs(1, 0);
    bit = Fenwick_Tree <int> (N);
    FOR(i, 1, N) {
        bit.update(time_in[i], -1);
        bit.update(time_out[i] + 1, 1);
    }
    while(M--) {
        int x; cin >> x;
        auto [u, v] = edges[x];
        if(anc[u][0] == v) swap(u, v);
        if(active[x]) {
            infor[v] = last_sync[v] = infor[find_anc(u)];
            bit.update(time_in[v], -1);
            bit.update(time_out[v] + 1, 1);
        } else {
            infor[find_anc(u)] += infor[v] - last_sync[v];
            bit.update(time_in[v], 1);
            bit.update(time_out[v] + 1, -1);
        }
        active[x] = !active[x];
    }

    while(Q--) {
        int x; cin >> x;
        cout << infor[find_anc(x)] << '\n';
    }
}

// Dream it. Wish it. Do it.

Compilation message (stderr)

synchronization.cpp: In instantiation of 'Fenwick_Tree<T>::Fenwick_Tree(int) [with T = int]':
synchronization.cpp:73:20:   required from here
synchronization.cpp:51:9: warning: 'Fenwick_Tree<int>::n' will be initialized after [-Wreorder]
   51 |     int n;
      |         ^
synchronization.cpp:50:15: warning:   'std::vector<int> Fenwick_Tree<int>::bit' [-Wreorder]
   50 |     vector<T> bit;
      |               ^~~
synchronization.cpp:52:5: warning:   when initialized here [-Wreorder]
   52 |     Fenwick_Tree(int _n = 0) : n(_n), bit(_n + 5){}
      |     ^~~~~~~~~~~~
synchronization.cpp: In function 'int main()':
synchronization.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:28:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 10 / 10
• Subtask 4: 20 / 20
• Subtask 5: 40 / 40