Submission #1285746

#	Time	Username	Problem	Language	Result	Execution time	Memory
1285746		thaibeo123	Synchronization (JOI13_synchronization)	C++20	0 / 100	134 ms	22104 KiB

synchronization

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

#define NAME "A"
#define ll long long
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define MASK(x) (1ll << (x))
#define BIT(x, i) (((x) >> (i)) & 1)

const int N = 3e5 + 5;
const int LG = 18;

struct FenwickTree {
    int n;
    vector<int> fen;

    FenwickTree() {}
    FenwickTree(int n): n(n), fen(n + 5) {}

    void update(int x, int v) {
        for (int i = x; i <= n; i += i & -i) {
            fen[i] += v;
        }
    }

    int get(int x) {
        int res = 0;
        for (int i = x; i > 0; i -= i & -i) {
            res += fen[i];
        }
        return res;
    }
};

int n, m, q, timer;
int tin[N], tout[N], hi[N], L[N][21], last[N], ans[N];
bool state[N];
FenwickTree fen;
vector<int> g[N];
pair<int, int> e[N];

int root(int x) {
    int res = x;
    for (int i = LG; i >= 0; i--) {
        if (L[x][i] == 0) continue;
        if (fen.get(tin[x]) - fen.get(tin[L[x][i]]) == 0) {
            res = L[x][i];
        }
    }
    return res;
}

void dfs(int u, int par) {
    hi[u] = hi[par] + 1;
    tin[u] = ++timer;
    L[u][0] = par;
    for (int i = 1; i <= LG; i++) {
        L[u][i] = L[L[u][i - 1]][i - 1];
    }

    for (int v : g[u]) {
        if (v == par) continue;
        dfs(v, u);
    }
    tout[u] = timer;
}

void input() {
    cin >> n >> m >> q;
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
        e[i] = {u, v};
    }
}

void solve() {
    dfs(1, 0);
    fen = FenwickTree(n);
    for (int i = 1; i < n; i++) {
        if (hi[e[i].fi] > hi[e[i].se]) {
            swap(e[i].fi, e[i].se);
        }
        fen.update(tin[i + 1], 1);
        fen.update(tout[i + 1] + 1, -1);
    }
    for (int i = 1; i <= n; i++) {
        ans[i] = 1;
    }

    while (m--) {
        int cur;
        cin >> cur;
        state[cur] = state[cur] ^ 1;
        int u = e[cur].fi, v = e[cur].se;
        if (state[cur] == 1) {
            fen.update(tin[v], -1);
            fen.update(tout[v] + 1, 1);
            ans[root(u)] += ans[v] - last[v];
        }
        else {
            fen.update(tin[v], 1);
            fen.update(tout[v] + 1, -1);
            last[v] = ans[v] = ans[root(u)];
        }
    }

    while (q--) {
        int x;
        cin >> x;
        cout << ans[root(x)] << "\n";
    }
}

signed main() {
    if (fopen(NAME".INP", "r")) {
        freopen(NAME".INP", "r", stdin);
        freopen(NAME".OUT", "w", stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    input();
    solve();

    return 0;
}

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:122:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |         freopen(NAME".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:123:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  123 |         freopen(NAME".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 10
• Subtask 4: 0 / 20
• Subtask 5: 0 / 40