Submission #1265777

#	Time	Username	Problem	Language	Result	Execution time	Memory
1265777		son2008	Synchronization (JOI13_synchronization)	C++20	100 / 100	197 ms	30292 KiB

synchronization

#include <bits/stdc++.h>
using namespace std;
#define task "task"
#define ii pair<int, int>
#define fi first
#define se second
// #define int long long
#define ll long long
#define ld double
#define mp make_pair
#define lg2 30
#define iii pair<ll, ii>
#define iiii pair<ii, ii>
#define base 29
#define eps 1e-8
int dx[] = {0LL, 0LL, 1, -1, 1, 1, -1, -1};
int dy[] = {1, -1, 0LL, 0LL, 1, -1, 1, -1};
const int maxn = 2e5 + 5, maxm = 1e4 + 5, maxq = 1e5 + 5;
const int mod = 1e9 + 7;
int n, m, q;
ii b[maxn];
int tin[maxn], tout[maxn], timer;
int h[maxn], P[maxn][lg2 + 1];
bool check[maxn];
int thua[maxn], ans[maxn];
vector<int> a[maxn];
struct FEN
{
    int n;
    vector<int> bit;
    FEN() {};
    FEN(int _n) : bit(n + 1, 0), n(_n + 1) {
                  };
    int get(int r)
    {
        int ret = 0;
        for (; r >= 0; r = (r & (r + 1)) - 1)
            ret += bit[r];
        return ret;
    }

    int get(int l, int r)
    {
        return get(r) - get(l - 1);
    }

    void update(int idx, int delta)
    {
        for (; idx < n; idx = idx | (idx + 1))
            bit[idx] += delta;
    }

    void updateRange(int l, int r, int val)
    {
        update(l, val);
        update(r + 1, -val);
    }
} bit;
void dfs(int u, int cha)
{
    ans[u] = 1;
    tin[u] = ++timer;
    for (int v : a[u])
    {
        if (v == cha)
            continue;
        h[v] = h[u] + 1;
        P[v][0] = u;
        dfs(v, u);
    }
    tout[u] = timer;
}
void build_lca()
{
    for (int j = 1; j <= lg2; j++)
    {
        for (int i = 1; i <= n; i++)
            P[i][j] = P[P[i][j - 1]][j - 1];
    }
}
int up(int u)
{
    for (int i = lg2; i >= 0; i--)
    {
        if (P[u][i] && bit.get(tin[u]) - bit.get(tin[P[u][i]]) == (1 << i))
        {
            u = P[u][i];
        }
    }
    return u;
}
void init()
{
    cin >> n >> m >> q;
    bit = FEN(n);
    for (int i = 1; i < n; i++)
    {
        int u, v;
        cin >> u >> v;
        a[u].push_back(v);
        a[v].push_back(u);
        b[i] = {u, v};
    }
}
void process()
{
    dfs(1, -1);
    build_lca();
    while (m--)
    {
        int id;
        cin >> id;
        int u = b[id].fi, v = b[id].se;
        if (h[u] > h[v])
            swap(u, v);
        if (!check[id])
        {
            ans[up(u)] += ans[v] - thua[id];
            bit.updateRange(tin[v], tout[v], 1);
        }
        else
        {
            ans[v] = thua[id] = ans[up(u)];
            bit.updateRange(tin[v], tout[v], -1);
        }
        check[id] ^= 1;
    }
    while (q--)
    {
        int x;
        cin >> x;
        cout << ans[up(x)] << '\n';
    }
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".inp", "r"))
    {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }
    int t = 1;
    //  cin>>t;
    while (t--)
    {
        init();
        process();
    }
    cerr << endl
         << "TIME : " << clock() * 0.001 << "s" << endl;
}

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:142:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  142 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:143:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  143 |         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