Submission #968281

#	Time	Username	Problem	Language	Result	Execution time	Memory
968281		Beerus13	Synchronization (JOI13_synchronization)	C++14	100 / 100	203 ms	30128 KiB

synchronization

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
const int N = 2e5 + 5;
const int K = 18;

int n, m, q, numDFS;
int P[N][K], in[N], out[N], bit[N], last_val[N], res[N];
pii edge[N];
bool vs[N];
vector<int> g[N];

void update(int i, int val) {
    for(; i <= n; i += i & -i) bit[i] += val;
}

void update(int l, int r, int val) {
    update(l, val);
    update(r + 1, -val);
}

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

int find(int u) {
    for(int i = K - 1; i >= 0; --i) {
        // check xem co cung tplt ko
        if(get(in[u]) == get(in[P[u][i]])) {
            u = P[u][i];
        }
    }
    return u;
}

void dfs(int u, int p = 0) {
    in[u] = ++numDFS;
    P[u][0] = p;
    for(int i = 1; i < K; ++i) P[u][i] = P[P[u][i - 1]][i - 1];
    for(int v : g[u]) if(v != p) {
        dfs(v, u);
    }
    out[u] = numDFS;
}

void solve() {
    cin >> n >> m >> q;
    for(int i = 1, u, v; i < n; ++i) {
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
        edge[i] = make_pair(u, v);
    }
    dfs(1);
    for(int i = 1; i <= n; ++i) {
        res[i] = 1;
        update(in[i], out[i], 1);
    }
    for(int i = 1, pos; i <= m; ++i) {
        cin >> pos;
        auto [u, v] = edge[pos];
        if(in[u] > in[v]) swap(u, v);
        if(!vs[pos]) {
            int rt = find(u);
            // join (rt, v) : rt = root(u), v = root(v)
            int nw = res[rt] + res[v] - last_val[pos];
            res[rt] = nw;
            update(in[v], out[v], -1);
        } else {
            res[v] = last_val[pos] = res[find(u)];
            update(in[v], out[v], 1);
        }
        vs[pos] ^= 1;
    }
    while(q--) {
        int u; cin >> u;
        cout << res[find(u)] << '\n';
    }
}


signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int test = 1;
    // cin >> test;
    while(test--) solve();
    return 0;
}

Compilation message (stderr)

synchronization.cpp: In function 'void solve()':
synchronization.cpp:64:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   64 |         auto [u, v] = edge[pos];
      |              ^

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